Implantable Electroacupuncture System and Method for Treating Depression and Similar Mental Conditions

ABSTRACT

An implantable electroacupuncture device (IEAD) treats mental illness through application of stimulation pulses applied at a specified tissue location, including at least one of acupoints GV20 and EXHN3, or their underlying nerves. In one embodiment, the IEAD comprises an implantable, coin-sized, self-contained, leadless electroacupuncture device having at least two electrodes attached to an outside surface of its housing. The device generates stimulation pulses in accordance with a specified stimulation regimen. Power management circuitry within the device allows a primary battery, having a high internal impedance, to be used to power the device. The stimulation regimen generates stimulation pulses during a stimulation session of duration T3 minutes applied every T4 minutes. The duty cycle, or ratio T3/T4 is very low, no greater than 0.05. The low duty cycle and careful power management allow the IEAD to perform its intended function for several years.

RELATED APPLICATIONS

This application claims the benefit of the following previously-filedprovisional patent applications, each of which is incorporated herein byreference:

-   -   1. VT11-003-01, Implantable Electroacupuncture Device and Method        For Treating Depression and Epilepsy, filed Sep. 29, 2011, Appl.        No. 61/541,061;    -   2. VT12-002-01, Electrode Configuration For Implantable        Electroacupuncture Device, filed Mar. 6, 2012, Appl. No.        61/606,995;    -   3. VT12-003-01. Boost Converter Output Control For Implantable        Electroacupuncture Device, filed Mar. 12, 2012, Appl. No.        61/609,875;    -   4. VT12-003-02, Boost Converter Circuit Surge Control For        Implantable Electroacupuncture Device Using Digital Pulsed        Shutdown, filed Jul. 16, 2012, Appl. No. 61/672,257;    -   5. VT12-004-01, Smooth Ramp-Up Stimulus Amplitude Control For        Implantable Electroacupuncture Device, filed Jul. 17, 2012,        Appl. No. 61/672,661;    -   6. VT12-005-01, Battery Transient Current Reduction In An        Implantable Electroacupuncture Device, filed Jul. 19, 2012,        Appl. No. 61/673,254;    -   7. VT12-006-01, Pulse Charge Delivery Control In An Implantable        Electroacupuncture Device, filed Jul. 23, 2012, Appl. No.        61/674,691;    -   8. VT12-008-01, Radial Feed-Through Packaging For An Implantable        Electroacupuncture Device, filed Jul. 26, 2012, Appl. No.        61/676,275.

BACKGROUND

Depression is a chronic illness involving the mind and body. It is alsocalled “major depression,” “major depressive disorder,” and “clinicaldepression.”The American Psychiatric Association publishes a model forthe classification of mental disorders. According to the model,“DSM-IV-TR,” a person is suffering from a major depressive episode if heor she experiences items 1 or 2 from the list of symptoms below, alongwith any four others, continuously for more than two weeks:

-   -   1. Depressed mood with overwhelming feelings of sadness and        grief.    -   2. Apathy—loss of interest and pleasure in activities formerly        enjoyed.    -   3. Sleep problems—insomnia, early-morning waking, or        oversleeping nearly every day.    -   4. Decreased energy or fatigue.    -   5. Noticeable changes in appetite and weight (significant weight        loss or gain).    -   6. Inability to concentrate or think, or indecisiveness.    -   7. Physical symptoms of restlessness or being physically slowed        down.    -   8. Feelings of guilt, worthlessness, and helplessness.    -   9. Recurrent thoughts of death or suicide, or a suicide attempt.

The prevalence of depression in the United States is profound, withalmost 8% of the adult population suffering from at least one episode ofmajor depression in the year 2007. The problem is serious andmedications are insufficient to resolve the chronic illness for manyadults.

The most common treatment options for depression are medications andpsychotherapy. Disadvantageously, only about thirty percent of patientsreach full remission after a first medication. Moreover, the sideeffects of medications are serious, including but not limited to weightgain, sexual dysfunction, nausea, drowsiness, and fatigue. It isimportant to start treatment for depression early because the illnessbecomes more difficult to treat after its initial onset. Further,patients respond to treatments differently. Hence, it becomes veryimportant to try different medications and alternative treatments if theinitial treatment(s) is not effective. Alternative treatments known inthe art used to treat depression are discussed below.

Generalized Anxiety Disorder (or “Anxiety” for short) is characterizedby excessive, recurrent, and prolonged anxiety and worrying. See,Swartz, K L. The Johns Hopkins White Papers: Depression and Anxiety.2011. Johns Hopkins Medicine. People with Anxiety typically agonize overeveryday concerns like job responsibilities, finances, health, or familywell-being. They may even agonize about minor matters like householdchores, car repairs, being late for appointments, or personalappearances. The focus of such anxiety may shift from one concern to thenext and the severity of sensations may range from mild tension andnervousness to feelings of dread.

Anxiety affects about three percent of adult Americans each year. Whilepeople with the disorder know that the intensity, duration and frequencyof their anxiety are generally unreasonably high, long, or frequent,they still have difficulty controlling their emotions.

Continued anxiety may impair concentration, memory, decision-making,attention span, and confidence. While the effect of Anxiety on everydayactivities is generally known, Anxiety may also produce physicalsymptoms including heart palpitations, restlessness, sweating,headaches, and nausea.

Tetracyclics and Selective Serotonin Reuptake Inhibitors (SSRIs) are thefirst line of treatment for anxiety. Serotonin and norepinephrinereuptake inhibitors are also often used. While anti-depressants aregenerally the first medications given to treat Anxiety, a person withAnxiety may not be depressed.

Bipolar disorder affects about three percent of American men and womenat some point in their lives. A person with the disorder typically hasalternating periods of major depression and mania. In rare cases, maniacan occur on its own. Episodes of mania are described as distinctperiods of abnormally and persistently elevated, expansive, or irritablemood. Such episodes are severe enough to cause trouble at work, home, orboth. The episodes can cause impaired judgment and often, excessiveinvolvement in high-risk behavior. The time between episodes can varygreatly and men with bipolar disorder seem to have more manic episodeswhile women have more depressive episodes.

Post-traumatic stress disorder (hereafter, “PTSD”) is a form of chronicpsychological stress that follows exposure to a traumatic event, such asa natural disaster, a violent crime, an accident, terrorism, or warfare.See, Swartz 2011. The symptoms are many, including not exclusively:recurrent, intrusive, distressing dreams and memories of the trauma; asudden sense that the event is recurring or the experience offlashbacks; extreme distress when confronted with events that remind aperson of the trauma; attempting to avoid thoughts, feelings, andactivities associated with the event; the inability to remember aspectsof the trauma; an exaggerated startle response; and, depression likesymptoms. The symptoms must last at least one month to be consideredPTSD. Symptoms may begin within six months of the trauma, they may beginafter six months, or they may persist for longer than six months. About3.5 percent of adult Americans develop PTSD each year. See, Swartz 2011.

Schizophrenia is a group of brain disorders in which patients interpretreality abnormally. The group includes paranoid, disorganized,catatonic, undifferentiated, and residual schizophrenia. It distorts theway a person thinks, acts, expresses himself, interprets reality, andrelates to others. While it is not known what causes schizophrenia,researchers believe it is a combination of genetics and environment.Neuroimaging studies support the notion that schizophrenia is a braindisorder; there are differences in the brain structure and centralnervous system in people with schizophrenia. Additionally, problems withsome naturally occurring brain chemicals like the neurotransmittersdopamine and glutamate are thought to contribute.

Obsessive Compulsive Disorder (hereafter, “OCD”) is characterized byunreasonable thoughts and fears (obsessions) that lead one to repetitivebehaviors (compulsions). See, Swartz 2011. People with OCD recognizethat their obsessions and compulsions are unreasonable, unnecessary,intrusive, and sometimes even foolish, but they cannot resist them.Obsessions are defined as recurring and persistent thoughts, ideas,images, or impulses, sometimes of an aggressive nature, that seem toinvade a person's consciousness. The patient will try to ignore theseuncomfortable thoughts often recognizing that they are unrealistic.Common obsessions are fear of contamination from germs, thoughts ofviolent behavior such as killing a family member, fear of making amistake or of harming oneself or others, and a constant need forreassurance. Compulsions are those ritualistic, repetitive, andpurposeful behaviors that arise from one's obsessions. The behavior isexcessive but seems to temporarily relieve the patient of stressregarding his or her obsessions.

About 1% of adult Americans have OCD each year. See, Swartz 2011. Someare able to keep their obsessions and compulsions more or less a secretwhile others may be incapacitated by their obsessive behavior.Depression is the most common complication of the disorder.

An alternative approach for treating depression, bipolar disorder,Anxiety, and a host of other physiological conditions, illnesses,deficiencies and disorders is acupuncture, which includes traditionalacupuncture and acupressure. Acupuncture has been practiced in Easterncivilizations (principally China, but also other Asian countries) for atleast 2500 years. It is still practiced today throughout many parts ofthe world, including the United States and Europe. A good summary of thehistory of acupuncture, and its potential applications may be found inCheung, et al., “The Mechanism of Acupuncture Therapy and Clinical CaseStudies”, (Taylor & Francis, publisher) (2001) ISBN 0-415-27254-8,hereafter referred to as “Cheung, Mechanism of Acupuncture, 2001.” TheForward, as well as Chapters 1-3, 5, 7, 8, 12 and 13 of Cheung,Mechanism of Acupuncture, 2001, are incorporated herein by reference.

Despite the practice in Eastern countries for over 2500 years, it wasnot until President Richard Nixon visited China (in 1972) thatacupuncture began to be accepted in the West, such as the United Statesand Europe. One of the reporters who accompanied Nixon during his visitto China, James Reston, from the New York Times, received acupuncture inChina for post-operative pain after undergoing an emergency appendectomyunder standard anesthesia. Reston experienced pain relief from theacupuncture and wrote about it in The New York Times. In 1973 theAmerican Internal Revenue Service allowed acupuncture to be deducted asa medical expense. Following Nixon's visit to China, and as immigrantsbegan flowing from China to Western countries, the demand foracupuncture increased steadily. Today, acupuncture therapy is viewed bymany as a viable alternative form of medical treatment, alongsideWestern therapies. Moreover, acupuncture treatment is now covered, atleast in part, by most insurance carriers. Further, payment foracupuncture services consumes a not insignificant portion of healthcareexpenditures in the U.S. and Europe. See, generally, Cheung, Mechanismof Acupuncture, 2001, vii.

Acupuncture is an alternative medicine that treats patients by insertionand manipulation of needles in the body at selected points. See, Novak,Patricia D. et al (1995). Dorland's Pocket Medical Dictionary (25thed.), Philadelphia: (W.B. Saunders Publisher), ISBN 0-7216-5738-9. Thelocations where the acupuncture needles are inserted are referred toherein as “acupuncture points” or simply just “acupoints”. The locationof acupoints in the human body has been developed over thousands ofyears of acupuncture practice, and maps showing the location ofacupoints in the human body are readily available in acupuncture booksor online. For example, see, “Acupuncture Points Map,” found online at:http://www.acupuncturehealing.org/acupuncture-points-map.html. Acupointsare typically identified by various letter/number combinations, e.g.,L6, S37. The maps that show the location of the acupoints may alsoidentify what condition, illness or deficiency the particular acupointaffects when manipulation of needles inserted at the acupoint isundertaken.

References to the acupoints in the literature are not always consistentwith respect to the format of the letter/number combination. Someacupoints are identified by a name only, e.g., Tongli. The same acupointmay be identified by others by the name followed with a letter/numbercombination placed in parenthesis, e.g., Tongli (HT5). Alternatively,the acupoint may be identified by its letter/number combination followedby its name, e.g., HT5 (Tongli). The first letter typically refers to abody organ, or other tissue location associated with, or affected by,that acupoint. However, usually only the letter is used in referring tothe acupoint, but not always. Thus, for example, the acupoint GV20 isthe same as acupoint Governing Vessel 20 which is the same as GV-20which is the same as GV 20 which is the same as Baihui. For purposes ofthis patent application, unless specifically stated otherwise, allreferences to acupoints that use the same name, or the same first letterand the same number, and regardless of slight differences in secondletters and formatting, are intended to refer to the same acupoint.

An excellent reference book that identifies all of the traditionalacupoints within the human body is WHO STANDARD ACUPUNCTURE POINTLOCATIONS IN THE WESTERN PACIFIC REGION, published by the World HealthOrganization (WHO), Western Pacific Region, 2008 (updated and reprinted2009), ISBN 978 92 9061 248 7 (hereafter “WHO Standard Acupuncture PointLocations 2008”). The Table of Contents, Forward (page v-yl) and GeneralGuidelines for Acupuncture Point Locations (pages 1-21), as well aspages 203 and 213 (which illustrate with particularity the location ofacupoint GV20) of the WHO Standard Acupuncture Point Locations 2008 areincluded herewith as Appendix D. Also included in Appendix D are threepages from the book: Quirico P E, Pedrali T. Teaching Atlas forAcupuncture. Volume 1: Channels and Points (2007), which pages show andhave been annotated to show additional detail for acupoints GV20 andEXHN3 and their surround areas.

While many in the scientific and medical community are highly criticalof the historical roots upon which acupuncture has developed, (e.g.,claiming that the existence of meridians, qi, yin and yang, and the likehave no scientific basis), see, e.g.,http://en.wikipedia.org/wiki/Acupuncture, few can refute the vast amountof successful clinical and other data, accumulated over centuries ofacupuncture practice, that shows needle manipulation applied at certainacupoints is quite effective.

The World Health Organization and the United States' National Institutesof Health (NIH) have stated that acupuncture can be effective in thetreatment of neurological conditions and pain. Reports from the USA'sNational Center for Complementary and Alternative Medicine (NCCAM), theAmerican Medical Association (AMA) and various USA government reportshave studied and commented on the efficacy of acupuncture. There isgeneral agreement that acupuncture is safe when administered bywell-trained practitioners using sterile needles, but not on itsefficacy as a medical procedure.

An early critic of acupuncture, Felix Mann, who was the author of thefirst comprehensive English language acupuncture textbook Acupuncture:The Ancient Chinese Art of Healing, stated that “The traditionalacupuncture points are no more real than the black spots a drunkard seesin front of his eyes.” Mann compared the meridians to the meridians oflongitude used in geography—an imaginary human construct. Mann, Felix(2000). Reinventing acupuncture: a new concept of ancient medicine.Oxford: Butterworth-Heinemann. pp. 14; 31. ISBN 0-7506-4857-0. Mannattempted to combine his medical knowledge with that of Chinese theory.In spite of his protestations about the theory, however, he apparentlybelieved there must be something to it, because he was fascinated by itand trained many people in the West with the parts of it he borrowed. Healso wrote many books on this subject. H is legacy is that there is nowa college in London and a system of needling that is known as “MedicalAcupuncture”. Today this college trains doctors and Western medicalprofessionals only.

For purposes of this patent application, the arguments for and againstacupuncture are interesting, but not that relevant. What is important isthat a body of literature exists that identifies several acupointswithin the human body that, rightly or wrongly, have been identified ashaving an influence on, or are otherwise somehow related to, thetreatment of various physiological conditions, deficiencies orillnesses, including mental illness. With respect to these acupoints,the facts speak for themselves. Either these points do or do not affectthe conditions, deficiencies or illnesses with which they have beenlinked. The problem lies in trying to ascertain what is fact from whatis fiction. This problem is made more difficult when conducting researchon this topic because the insertion of needles, and the manipulation ofthe needles once inserted, is more of an art than a science, and resultsfrom such research become highly subjective. What is needed is a muchmore regimented approach for doing acupuncture research.

It should also be noted that other medical research, not associated withacupuncture research, has over the years identified nerves and otherlocations throughout a patient's body where the application ofelectrical stimulation produces a beneficial effect for the patient.Indeed, the entire field of neurostimulation deals with identifyinglocations in the body where electrical stimulation can be applied inorder to provide a therapeutic effect for a patient. For purposes ofthis patent application, such known locations within the body aretreated essentially the same as acupoints—they provide a “target”location where electrical stimulation may be applied to achieve abeneficial result, whether that beneficial result is to reduce pain, totreat cardiovascular disease, to treat mental illness, or to addresssome other issue associated with a disease or condition of the patient.

Returning to the discussion regarding acupuncture, some have proposedapplying moderate electrical stimulation at selected acupuncture pointsthrough needles that have been inserted at those points. See, e.g.,http://en.wikipedia.org/wiki/Electroacupuncture. Such electricalstimulation is known as electroacupuncture (EA). According toAcupuncture Today, a trade journal for acupuncturists:“Electroacupuncture is quite similar to traditional acupuncture in thatthe same points are stimulated during treatment. As with traditionalacupuncture, needles are inserted on specific points along the body. Theneedles are then attached to a device that generates continuous electricpulses using small clips. These devices are used to adjust the frequencyand intensity of the impulse being delivered, depending on the conditionbeing treated. Electroacupuncture uses two needles at a time so that theimpulses can pass from one needle to the other. Several pairs of needlescan be stimulated simultaneously, usually for no more than 30 minutes ata time.” “Acupuncture Today: Electroacupuncture”. 2004 Feb. 1 (retrievedon-line 2006 Aug. 9 athttp://www.acupuncturetoday.com/abc/electroacupuncture.php).

U.S. Pat. No. 6,735,475, issued to Whitehurst et al., discloses use ofan implantable miniature neurostimulator, referred to as a“microstimulator,” that can be implanted into a desired tissue locationand used as a therapy for headache and/or facial pain. Themicrostimulator has a tubular shape, with electrodes at each end.Stimulation of the Trigeminal nerve is mentioned in the patent, but notfor purposes of treating depression.

Other patents of Whitehurst et al. teach the use of this small,microstimulator, placed in other body tissue locations, including withinan opening extending through the skull into the brain, for the treatmentof a wide variety of conditions, disorders and diseases. See, e.g., U.S.Pat. No. 6,950,707 (obesity and eating disorders); U.S. Pat. No.7,003,352 (epilepsy by brain stimulation); U.S. Pat. No. 7,013,177 (painby brain stimulation); U.S. Pat. No. 7,155,279 (movement disordersthrough stimulation of Vagus nerve with both electrical stimulation anddrugs); U.S. Pat. No. 7,292,890 (Vagus nerve stimulation); U.S. Pat. No.7,203,548 (cavernous nerve stimulation); U.S. Pat. No. 7,440,806(diabetes by brain stimulation); U.S. Pat. No. 7,610,100(osteoarthritis); and U.S. Pat. No. 7,657,316 (headache by stimulatingmotor cortex of brain).

Recently, some promising experimental neuromodulation approaches for thetreatment of depression through stimulation of the Trigeminal nerve haveappeared. See, e.g., “Non-Invasive Therapy Significantly ImprovesDepression, Researchers Say,” ScienceDaily.com (Sep. 6, 2010);“Trigeminal nerve stimulation significantly improves depression”,www.psypost.org, Friday, Sep. 3, 2010; Lewis, D. “Trigeminal NerveStimulation for Depression,” www.helpforDpression.com (Sep. 15, 2011).

Further, there is at least one company, NeuroSigma, Inc., of Westwood,Calif., that is developing and commercializing neuromodulationtreatments for a variety of disorders, including epilepsy, depression,post-traumatic stress disorder (PTSD), obesity, and cachexia. Thetherapy platforms used by NeuroSigma at the present comprise TrigeminalNerve Stimulation (TNS) and Deep Brain Stimulation (DBS). See, e.g., theweb site of NeuroSigma, Inc., found at http://www.neurosigma.com/.

U.S. Patent Publications of DeGiorgio et al., US 2011/0106220, publishedMay 5, 2011; US 2011/0112603 A1, published May 12, 2011; US 2011/0218859A1, published Sep. 8, 2011; and US 2011/0218590 A1, published Sep. 8,2011, describe and disclose, in some detail, the devices and methodsused by NeuroSigma, Inc. in carrying out its TNS therapy platform forthe treatment of depression and epilepsy, and other neurological orneuropsychiatric disorders. The four published patent applicationsreferenced in this paragraph are incorporated herein by reference intheir entireties. These four published patent applications appear to beassigned to The Regents of the University of California. The Regents ofthe University of California, in turn, appear to have recently executedan exclusive worldwide license for Trigeminal Nerve Stimulation (TNS)with NeuroSigma Inc., as reported in Science Daily (Sep. 6, 2010). See,e.g., the news release found athttp://www.sciencedaily.com/releases/2010/09/110903092507.htm.

In general, two of the above four published US patent applications ofDeGiorgio et al., US 2011/0112603 A1, published May 12, 2011 (hereafterthe “'603 Publication”) and US 2011/0218590 A1, published Sep. 8, 2011(hereafter the “'590 Publication”), relate primarily to TNS stimulationfor treatment of depression and other mood disorders using eithercutaneous electrodes (590 Publication) or using at least one implantableelectrode (603 Publication). The other two of the above four publishedUS Patent applications, US 2011/0106220, published May 5, 2011(hereafter the “'220 Publication”) and US 2011/0218859 A1, publishedSep. 8, 2011 (hereafter the “'859 Publication”), relate primarily to TNSstimulation for treatment of epilepsy and other neurological disordersand conditions using either cutaneous electrodes (589 Publication) orusing at least one implantable electrode ('220 Publication).

In the two DeGiorgio et al. published patent applications where animplantable electrode is used, electrical connection with theimplantable electrode occurs by either (i) connecting an implantedelectrical cable between the implantable electrode contacts and animplanted neurostimulator, see, e.g., the '603 Publication at Paragraph[0060], or (ii) making a wireless electrical connection between anexternal, non-implanted neurostimulator and the implantable electrodeassembly through the use of inductive coupling. Id. Either way, whenimplantable electrode contacts are employed, there must either besignificant tunneling through the tissue to allow a connecting cable tomake electrical connection between the implanted neurostimulator deviceand electrode contacts, or additional circuitry with its accompanyingcomplexity (and associated increased power consumption) must be employedwithin the external neurostimulator and/or the implanted electrodecontacts to facilitate an enhanced inductively coupled connection.

Insofar as Applicant is aware, the '603 Publication represents thecurrent state of the art for treating depression using implantabledevices and methods that stimulate the Trigeminal nerve. Similarly, the'220 Publication represents the current state of the art for treatingepilepsy using implantable devices and methods that stimulate theTrigeminal nerve. However, while the advance in the art described andpresented in the '603 and '220 Publications is significant over priorneuromodulation therapy techniques for treating depression or epilepsy,improvements are still needed. For example, when implantable electrodecontacts are employed, an efficient and safe mechanism must still beemployed to electrically (or optically, or magnetically) connect theelectrode contacts to a suitable pulse generator. If the pulse generatoris external (non-implanted), either (i) the leads must pass through theskin (not a good thing to do over time because of infections and otherconcerns), or (ii) some sort of signal coupling mechanism, such asinductive or rf coupling, must be employed to allow the pulses generatedby the pulse generator to be efficiently transferred to the electrodearray and to specific electrode contacts included within the electrodearray. If the pulse generator is implanted, a cable or lead must betunneled through the body tissue from the implant location of the pulsegenerator to the implant location of the electrode contacts. Tunnelingthrough body tissue, especially over a long distance, suffers from allthe same risks associated with major surgery, as well as createsproblems for the patient in the event of lead malfunction or breakage.Thus, it is seen that despite the advances made in the art, improvementsare still needed.

Techniques for using electrical devices, including external EA devices,for stimulating peripheral nerves and other body locations for treatmentof various maladies are known in the art. See, e.g., U.S. Pat. Nos.4,535,784; 4,566,064; 5,195,517; 5,250,068; 5,251,637; 5,891,181;6,393,324; 6,006,134; 7,171,266; and 7,171,266. The two previouslyreferenced patent application publications of DeGiorgio et al. that useimplantable electrodes fall into this same category. Unfortunately, themethods and devices disclosed in these patents and applicationstypically utilize (i) large implantable stimulators having long leadsthat must be tunneled through tissue over an extended distance to reachthe desired stimulation site, (ii) external devices that must interfacewith implanted electrodes via percutaneous leads or wires passingthrough the skin, or (iii) inefficient and power-consuming wirelesstransmission schemes. Such devices and methods are still far tooinvasive, or are ineffective, and thus subject to the same limitationsand concerns, as are the previously described electrical stimulationdevices. From the above, it is seen that there is a need in the art fora less invasive device and technique for electroacupuncture stimulationof acupoints that does not require the continual use of needles insertedthrough the skin, or long insulated wires implanted or inserted intoblood vessels, for the purposes of treating mental illness.

SUMMARY

One characterization of the invention described herein is an ImplantableElectroAcupuncture System (IEAS) that treats depression and similarmental conditions through application of electroacupuncture (EA)stimulation pulses applied at a specified tissue location(s) of apatient. A key component of such IEAS is an implantableelectroacupuncture (EA) device. The EA device has a small,hermetically-sealed housing containing a primary power source, pulsegeneration circuitry powered by the primary power source, and a sensorthat wirelessly senses operating commands generated external to thehousing. The pulse generation circuitry generates stimulation pulses inaccordance with a specified stimulation regimen as controlled, at leastin part, by the operating commands sensed through the sensor. The EAdevice further includes a plurality of electrode arrays (where anelectrode array comprises an array of n conductive contacts electricallyjoined together to function jointly as one electrode, where n is aninteger) on the outside of the EA device housing that are electricallycoupled to the pulse generation circuitry on the inside of the EA devicehousing. Such electrical coupling occurs through at least onefeed-through terminal passing through a wall of the hermetically-sealedhousing. Stimulation pulses generated by the pulse generation circuitryinside of the EA device housing are directed to the electrode arrays onthe outside of the EA housing. The stimulation pulses are thus appliedat the specified tissue location through the plurality of electrodearrays in accordance with the specified stimulation regimen. Thespecified stimulation regimen defines how often a stimulation session (astimulation session comprises a stream of stimulation pulses) is appliedto the patient, and the duration of each stimulation session. Moreover,the stimulation regimen requires that the stimulation session be appliedat a very low duty cycle. More particularly, if the stimulation sessionhas a duration of T3 minutes and occurs at a rate of once every T4minutes, then the duty cycle, or the ratio of T3/T4, cannot be greaterthan 0.05. The specified tissue location whereat EA stimulation pulsesare applied comprises at least one of acupoints GV20 and EXHN3, or theirunderlying nerves, or one of the three branches of the Trigeminal nerve:supratrochlear, supraorbital or infraorbital (hereafter the “ThreeBranches” of the Trigeminal nerve).

Another characterization of the invention described herein is anImplantable ElectroAcupuncture System (IEAS) for treating depression andsimilar medical conditions. Such IEAS includes (a) an implantableelectroacupuncture (EA) device housing having a maximum linear dimensionof no more than 25 mm in a first plane, and a maximum height of no more2.5 mm in a second plane orthogonal to the first plane; (b) a primarybattery within the EA device housing having an internal impedance of noless than about 5 ohms; (c) pulse generation circuitry within the EAdevice housing and powered by the primary battery that generatesstimulation pulses during a stimulation session; (d) control circuitrywithin the EA device housing and powered by the primary battery thatcontrols the frequency of the stimulation sessions to occur no more thanonce every T4 minutes, and that further controls the duration of eachstimulation session to last no longer than T3 minutes, where the ratioof T3/T4 is no greater than 0.05; (e) sensor circuitry within the EAdevice housing and coupled to the control circuitry that is responsiveto the presence of a control command generated external to the EA devicehousing, which control command when received by the control circuitrysets the times T3 and T4 to appropriate values; and (f) a plurality ofelectrodes located outside of the EA device housing that areelectrically coupled to the pulse generation circuitry within the EAdevice housing. The plurality of electrodes are positioned to lie at ornear a target tissue location belonging to the group of target tissuelocations made up of acupoints GV20 and EXHN3, the nerves underlyingacupoints GV20 and EXHN3, or the Three Branches of the Trigeminal nerve.

Yet another characterization of the invention described herein is amethod for treating at least one of the following mental disorders of apatient: major depression disorder (MDD), generalized anxiety disorder(Anxiety), bipolar disorder, post-traumatic stress disorder (PTSD),schizophrenia, and obsessive compulsive disorder (OCD). The methodincludes: (a) implanting an electroacupuncture (EA) device in thepatient below the patient's skin at or near at least one specifiedtarget tissue location; (b) enabling the EA device to generatestimulation sessions at a duty cycle that is less than or equal to 0.05,wherein each stimulation session comprises a series of stimulationpulses, and wherein the duty cycle is the ratio of T3/T4, where T3 isthe duration of each stimulation session, and T4 is the time or durationbetween stimulation sessions; and (c) delivering the stimulation pulsesof each stimulation session to at least one specified target tissuelocation through a plurality of electrode arrays electrically connectedto the EA device. Here, an electrode array comprises an array of nconductive contacts electrically joined together to function jointly asone electrode, where n is an integer. The at least one specified targettissue location at which the stimulation pulses are applied in thismethod is selected from the group of target tissue locations comprisingacupoints EXHN3 and GV20, or their underlying nerves, or the ThreeBranches of the Trigeminal nerve.

A further characterization of the invention described herein is a methodof treating at least one of the following mental disorders of a patient:major depression disorder (MDD), generalized anxiety disorder (Anxiety),bipolar disorder, post-traumatic stress disorder (PTSD), schizophrenia,and obsessive compulsive disorder (OCD) in a patient using a smallimplantable electroacupuncture device (IEAD). Such IEAD is powered by asmall disc primary battery having a specified nominal output voltage ofabout 3 volts and having an internal impedance of at least 5 ohms. TheIEAD is configured, using electronic circuitry within the IEAD, togenerate stimulation pulses in accordance with a specified stimulationregimen. These stimulation pulses are applied at a selected tissuelocation of the patient through at least two electrodes located outsideof the housing of the IEAD. The method comprises: (a) implanting theIEAD below the skin surface of the patient at or near a target tissuelocation selected from the group of target tissue locations comprisingacupoints EXHN3 and GV20 and their underlying nerves, and theinfraorbital branch of the trigeminal nerve; and (b) enabling the IEADto provide stimulation pulses in accordance with a stimulation regimenthat provides a stimulation session of duration T3 minutes at a rate ofonce every T4 minutes, where the ratio of T3/T4 is no greater than 0.05,and wherein T3 is at least 10 minutes and no greater than 72 minutes.

The invention described herein may additionally be characterized as amethod of assembling an implantable electroacupuncture device (IEAS) ina small, thin, hermetically-sealed, housing having a maximum lineardimension in a first plane of no more than 25 mm and a maximum lineardimension in a second plane orthogonal to the first plane of no morethan 2.5 mm. Such housing has at least one feed-through pin assemblyradially passing through a wall of the thin housing that isolates thefeed-through pin assembly from high temperatures and residual weldstresses that occur when the thin housing is welded shut tohermetically-seal its contents. The IEAD thus assembled is adapted foruse in treating mental disorders of a patient. The method comprises thesteps of:

-   -   (a) forming a thin housing having a bottom case and a top cover        plate, the top cover plate being adapted to fit over the bottom        case, the bottom case having a maximum linear dimension of no        more than 25 mm;    -   (b) forming a recess in a wall of the housing;    -   (c) placing a feed-through assembly within the recess so that a        feed-through pin of the feed-through assembly electrically        passes through a wall of the recess at a location that is        separated from where the wall of the housing is designed to        contact the top cover plate; and    -   (d) welding the top cover plate to the bottom case around a        perimeter of the bottom case, thereby hermetically sealing the        bottom case and top case together.

Yet another characterization of the invention described herein is anImplantable ElectroAcupuncture System (IEAS) for treating at least oneof the following mental disorders of a patient: major depressiondisorder (MDD), generalized anxiety disorder (Anxiety), bipolardisorder, post-traumatic stress disorder (PTSD), schizophrenia, andobsessive compulsive disorder (OCD). Such IEAS includes (a) at least oneexternal component, and (b) a small, thin implantable component having amaximum linear dimension in a first plane of less than 25 mm, and amaximum linear dimension in a second plane orthogonal to the first planof no more than 2.5 mm.

In one preferred embodiment, the external component comprises anelectromagnetic field generator. As used herein, the term“electromagnetic field” encompasses radio frequency fields, magneticfields, light emissions, or combinations thereof.

The implantable component includes a housing made of a bottom part and atop part that are welded together to create an hermetically-sealed,closed container. At least one feed-through terminal passes through aportion of a wall of the top part or bottom part. This terminal allowselectrical connection to be made between the inside of the closedcontainer and a location on the outside of the closed container.Electronic circuitry, including a power source, is included on theinside of the closed container that, when enabled, generates stimulationpulses during a stimulation session that has a duration of T3 minutes.The electronic circuitry also generates a new stimulation session at arate of once every T4 minutes. The ratio of T3/T4, or the duty cycle ofthe stimulation sessions, is maintained at a very low value of nogreater than 0.05. The stimulation pulses are coupled to the at leastone feed-through terminal, where they are connected to a plurality ofelectrodes/arrays located on an outside surface of the closed housing.The stimulation pulses contained in the stimulation sessions are thusmade available to stimulate body tissue in contact with or near theplurality of electrodes/arrays on the outside of the closed housing.

Further included on the inside of the closed container is a sensoradapted to sense the presence or absence of an electromagnetic field.Also included on the inside of the closed container is a power sourcethat provides operating power for the electronic circuitry.

In operation, the external component modulates an electromagnetic fieldwhich, when sensed by the sensor inside of the closed container, conveysinformation to the electronic circuitry inside of the closed housingthat controls when and how long the stimulation sessions are appliedthrough the plurality of electrodes/arrays. Once this information isreceived by the electronic circuitry, the external component can beremoved and the implantable component of the IEAS will carry out thestimulation regimen until the power source is depleted or newinformation is received by the electronic circuitry, whichever occursfirst.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the inventionwill be more apparent from the following more particular descriptionthereof, presented in conjunction with the following drawings. Thesedrawings illustrate various embodiments of the principles describedherein and are part of the specification. The illustrated embodimentsare merely examples and do not limit the scope of the disclosure.

FIGS. 1-17B relate to one preferred embodiment of the invention. FIGS.18-31 relate to general principles and concepts associated with theinvention.

FIG. 1 is a perspective view of an Implantable Electroacupuncture Device(IEAD) made in accordance with the teachings presented herein.

FIG. 1A illustrates the location of acupoint EXHN3 (also sometimesreferred to as acupoint GV24.5, or acupoint EX Yintang), one of the twoacupoints identified herein as a location to implant an IEAD for thetreatment of major depression disorder (MDD), generalized anxietydisorder (Anxiety), bipolar disorder, post-traumatic stress disorder(PTSD), schizophrenia, and obsessive compulsive disorder (OCD).

FIG. 1B depicts the location of acupoint GV20, the other of the twoacupoints identified herein as a location to implant the IEAD for thetreatment of MDD, Anxiety, bipolar disorder, PTSD, schizophrenia, andOCD.

FIG. 2 shows a plan view of one surface of the IEAD housing illustratedin FIG. 1.

FIG. 2A shows a side view of the IEAD housing illustrated in FIG. 1.

FIG. 3 shows a plan view of the other side, indicated as the “BackSide,” of the IEAD housing or case illustrated in FIG. 1.

FIG. 3A is a sectional view of the IEAD of FIG. 3 taken along the lineA-A of FIG. 3.

FIG. 4 is a perspective view of the IEAD housing, including afeed-through pin, before the electronic components are placed therein,and before being sealed with a cover plate.

FIG. 4A is a side view of the IEAD housing of FIG. 4.

FIG. 5 is a plan view of the empty IEAD housing shown in FIG. 4.

FIG. 5A depicts a sectional view of the IEAD housing of FIG. 5 takenalong the section line A-A of FIG. 5.

FIG. 5B shows an enlarged view or detail of the portion of FIG. 5A thatis encircled with the line B.

FIG. 6 is a perspective view of an electronic assembly, including abattery, that is adapted to fit inside of the empty housing of FIG. 4and FIG. 5.

FIGS. 6A and 6B show a plan view and side view, respectively, of theelectronic assembly shown in FIG. 6.

FIG. 7 is an exploded view of the IEAD assembly, illustrating itsconstituent parts.

FIG. 7A schematically illustrates a few alternative electrodeconfigurations that may be used with the invention.

FIG. 8A illustrates a functional block diagram of the electroniccircuits used within an IEAD of the type described herein.

FIG. 8B shows a basic boost converter circuit configuration, and is usedto model how the impedance of the battery R_(BAT) can affect itsperformance.

FIG. 9A illustrates a typical voltage and current waveform for thecircuit of FIG. 8 when the battery impedance R_(BAT) is small.

FIG. 9B shows the voltage and current waveform for the circuit of FIG.8B when the battery impedance R_(BAT) is large.

FIG. 10 shows one preferred boost converter circuit and a functionalpulse generation circuit configuration for use within the IEAD.

FIG. 11 shows an alternate boost converter circuit configuration and afunctional pulse generation circuit for use within the IEAD.

FIG. 12 shows a refinement of the circuit configuration of FIG. 11.

FIG. 13A shows one preferred schematic configuration for an implantableelectroacupunture device (IEAD) that utilizes the boost converterconfiguration shown in FIG. 10.

FIG. 13B shows current and voltage waveforms associated with theoperation of the circuit shown in FIG. 13A.

FIG. 14 shows another preferred schematic configuration for an IEADsimilar to that shown in FIG. 13A, but which uses an alternate outputcircuitry configuration for generating the stimulus pulses.

FIG. 15A shows a timing waveform diagram of representative EAstimulation pulses generated by the IEAD device during a stimulationsession.

FIG. 15B shows a timing waveform diagram of multiple stimulationsessions, and illustrates the waveforms on a more condensed time scale.

FIG. 16 shows a state diagram that shows the various states in which theIEAD may be placed through the use of an external magnet.

FIG. 17A illustrates one technique for implanting an IEAD under the skinin a location where a front surface of the IEAD faces inward toward theskull bone of the patient.

FIG. 17B depicts an alternative technique for implanting an IEAD in apocket formed in the skull bone below a desired acupoint, with a frontsurface of the IEAD facing outward towards the skin.

FIG. 18 is a block diagram that illustrates the two main components ofan Electroacupunture (EA) Stimulation System made as taught herein. SuchEA Stimulation System (also referred to herein as an “EA System”)includes: (1) an External Control Device (ECD); and (2) an ImplantableStimulator (also referred to herein as a “Implantable ElectroacupunctureDevice” or IEAD). Two variations of the IEAD are depicted, either one ofwhich could be used as part of the EA System, one having electrodesformed as an integral part of the IEAD housing, and another having theelectrodes at or near the distal end of a very short lead that isattached to the IEAD.

FIG. 18A is a Table that summarizes the functions performed by the twomain components of the EA System of FIG. 1A in accordance with variousconfigurations of the invention.

FIG. 19 is an illustration of the human head, and shows the location ofsome effective and ineffective acupoints used in electroacupuncture forthe treatment of depression, Anxiety, bipolar disorder and other mentalillnesses. This figure is taken from Quirico P E, Pedrali T. TeachingAtlas of Acupuncture, Volume 1: Channels and Points. Georg Theme Verlag.2007; page 186. A much more detailed representation of these and otheracupoints may be found in WHO Standard Acupuncture Point Locations 2008,selected portions of which may be found in Appendix D. Also, some basicacupoints associated with the head are illustrated in FIGS. 1A and 1B.

FIG. 20 shows the use of one type of electrode integrated within a frontside (the front side is usually—but not always—the side farthest awayfrom the skin when the device is implanted, and thus it is oftenreferred to as the “underneath” side) of a housing structure of aimplantable electroacupuncture device, or IEAD. This electrode isinsulated from the other portions of the IEAD housing, which otherportions of the housing structure may function as a return electrode forelectroacupuncture stimulation.

FIG. 20A is a sectional view, taken along the line A-A of FIG. 20, thatshows one embodiment or variation of the IEAD housing wherein theelectrode of FIG. 20 resides in a cavity formed within the front side ofthe IEAD.

FIG. 20B is a sectional view, taken along the line A-A of FIG. 20, andshows an alternative embodiment or variation of the front side of theIEAD housing wherein the electrode comprises a smooth bump thatprotrudes out from the underneath surface of the IEAD a short distance.

FIG. 20C is a sectional view, taken along the line A-A of FIG. 20, andshows yet an additional alternative embodiment or variation of the frontside of the IEAD housing wherein the electrode is at or near the distalend of a short lead that extends out a short distance from the frontside of, or an edge of, the IEAD housing.

FIG. 21 is similar to FIG. 20, but shows the use of an electrode arrayhaving four individual electrodes integrated within the housingstructure of an IEAD.

FIG. 21A is a sectional view, taken along the line B-B of FIG. 21, thatshows an embodiment where the electrodes comprise rounded bumps thatprotrude out from the front surface of the IEAD a very short distance.

FIG. 21B is likewise a sectional view, taken along the line B-B of FIG.21, that shows an alternative embodiment or variation where theelectrodes comprise tapering cones or inverted-pyramid shaped electrodesthat protrude out from the front surface of the IEAD a short distanceand end in a sharp tip, much like a needle.

FIG. 21C is a also a sectional view, taken along the line B-B of FIG.21, that shows yet another embodiment or variation of the front surfaceof the IEAD housing where the electrodes comprise small conductive padsformed at or near the distal end of a flex circuit cable (shown twisted90 degrees in FIG. 21C) that extends out from the front surface of theIEAD housing a short distance.

FIGS. 22A through 22E show various alternate shapes of the housing ofthe IEAD that may be used with an EA System. Each respective figure,FIG. 22A, FIG. 22B, FIG. 22C, and FIG. 22D show side sectional views ofthe housing shape, and FIG. 22E shows both a perspective view (labeledas “A”) and a side view (labeled as “B”) of the housing shape.

FIG. 23 is an electrical functional block diagram of the circuitry andelectrical components housed within an EA System which includes an IEADand External Controller in accordance with the various embodiments ofthe invention. The functional circuitry shown to the right of FIG. 23 iswhat is typically housed within the IEAD. The functional circuitry shownto the left of FIG. 23 is what is typically housed within the ExternalController. How much circuitry is housed within the IEAD and how much ishoused within the External Controller is a function of which embodimentof the EA System is being used.

FIG. 24 is an electrical functional block diagram of a passive IEAD(where “passive”, as used herein, means a circuit that generally employsonly wires or conductors, capacitors, or resistors, and requires nointernal power source). This passive IEAD is intended for use withEmbodiment III (FIG. 18).

FIG. 25A is an electrical functional block diagram of a voltagestimulation output stage that may be used within the IEAD (right side ofFIG. 23).

FIG. 25B is an electrical functional block diagram of a currentstimulation output stage that may be used within the IEAD (right side ofFIG. 23) instead of the voltage stimulation output state of FIG. 25A.

FIG. 26 illustrates one embodiment of a power source that may be usedwithin the IEAD which utilizes both a supercapacitor and a rechargeablebattery.

FIG. 27 is a timing diagram that illustrates a typical stimulationpattern of biphasic stimulation pulses used by the EA System, anddefines some of the operating parameters that may be programmed as partof the programmed stimulation regime.

FIG. 28 is likewise a timing diagram that illustrates, on a larger timescale than FIG. 27, various stimulation patterns and operatingparameters that may be programmed for use by the EA System.

FIG. 29 is a flowchart that illustrates a typical EA stimulation processor method for use with the EA stimulation system described herein.

FIG. 30 is a flowchart that illustrates a manually triggered EAstimulation process or method for use with the EA stimulation systemdescribed herein.

FIG. 31 is an alternate flowchart that illustrates anotherrepresentative EA stimulation process or method that may be used withsome embodiments of the IEAD described herein.

Appendix A, submitted herewith, illustrates some examples of alternatesymmetrical electrode configurations that may be used with an IEAD ofthe type described herein.

Appendix B, submitted herewith, illustrates a few examples ofnon-symmetrical electrode configurations that may be used with an IEADmade in accordance with the teachings herein.

Appendix C, submitted herewith, shows an example of the code used in themicro-controller IC (e.g., U2 in FIG. 14) to control the basic operationand programming of the IEAD, e.g., to Turn the IEAD ON/OFF, adjust theamplitude of the stimulus pulse, and the like, using only an externalmagnet as an external communication element.

Appendix D, submitted herewith, contains selected pages from the WHOStandard Acupuncture Point Locations 2008 reference book, referred to inparagraph [0017], as well as selected pages from other references.

Appendix E, submitted herewith, shows alternate case shapes andelectrode placements for an implantable EA device of the type disclosedherein.

Appendix F, submitted herewith, illustrates alternate approaches for usewith a short pigtail lead attached to the housing of the EA stimulationdevice.

Appendices A, B, C, D, E and F are incorporated by reference herein, andcomprise a part of the specification of this patent application.

Throughout the drawings and appendices, identical reference numbersdesignate similar, but not necessarily identical, elements.

DETAILED DESCRIPTION Overview

Disclosed and claimed herein is a small electroacupuncture (EA) device,having one or more electrodes formed within and as an integral part of,or anchored to, its housing. The EA device is adapted to be implantedthrough a small incision, e.g., less than 2-3 cm in length, directlyadjacent to a selected acupuncture site known to moderate or affect apatient's physiological or health condition that needs treatment. Inaccordance with the teachings herein, the small EA device is implantedso that its electrodes are located at, or near, a desired target tissuelocation, e.g., at a target acupuncture site. (An acupuncture site mayalso be referred to herein as an “acupoint.”)

Once the electrode(s) are anchored at the selected acupuncture site,electrical stimulation is applied using a low intensity, low frequencyand low duty cycle stimulation regime that is designed to achieve thesame or similar beneficial therapeutic effects as have previously beenobtained through conventional acupuncture treatments or nervestimulations. One of the primary advantages and benefits provided by theEA device disclosed herein (used to electrically stimulate acupoints) isthat an entire body of medicine (acupuncture, as developed and maturedover thousands of years) may be brought to the general populace with amuch more uniform approach than has heretofore been achievable.

As used herein, the term “EA device” may refer to either a smallImplantable NeuroStimulator (INS) designed for stimulating nerves and/orother body tissue at a precisely-defined location; or a smallimplantable electroacupuncture (EA) device, or “IEAD”, designed tostimulate an acupuncture site, or acupoint, where an “acupoint” isinherently defined as a precise tissue location. Thus, as used herein,IEAD=EA device=implanted neurostimulator ═INS. And, as used herein,acupoint=an acupuncture stimulation point=a target tissue/nervestimulation location where electrical pulses generated by aneurostimulator device, i.e., an EA device, are applied.

Also, as used herein, “electrode” and ‘electrode contact” or“electrodes” and “electrode contacts” or electrode array, are often usedinterchangeably to refer to that part of the EA device housing, or thatpart of a lead connected to an EA or INS device, from which electricalstimulation pulses, currents and/or voltages are applied to body tissue.

Applying the EA stimulation according to a prescribed stimulation regimeis an important key of the invention because it allows a more uniformhealth care approach to be followed for treatment of a particulardisorder or illness. Conventional acupuncture treatment, on the otherhand, relies heavily on the skill and experience of the acupuncturist,which may vary a great deal from acupuncturist to acupuncturist. Incontrast, electroacupuncture treatment as taught herein may be uniformlyapplied for a specific disorder or illness once the electrodes arepositioned at or near the correct acupoint, or other tissue locationknown to affect a condition being treated, and once the prescribedstimulation regime is shown to be effective.

Applying the EA stimulation at low intensities, low frequencies and lowduty cycles is also a key feature of the invention because it allows thepower source of the EA device to be small, yet still with sufficientcapacity to uniformly carry out the stimulation procedure (orstimulation regime) for several years, thereby reducing the amount oftime a patient has to spend at the office of medical personnel who aremonitoring or otherwise overseeing the patient's treatment.

Further, having the EA device be small, with the electrodes an integralpart of the housing of the device, or in very close proximity of thedevice at the distal end of a very short lead, overcomes the limitationsof having to use a large pulse generator implanted in the trunk of thepatient's body and thereafter having an insulated lead wire tunneledthrough the limbs to an acupuncture point. (It is noted that the use ofa large pulse generator in the body's trunk, with long leads tunneledthrough tissue or blood vessels to the needed acupoint is the currentstate of the art in implanted electroacupuncture art, as evidenced,e.g., in U.S. Pat. No. 7,373,204).

A preferred EA device made in accordance with the teachings of theinvention is thus small, and has a mechanical shape or envelope thatmakes it easy to implant through a small incision made near or at theacupuncture site. The EA device may be configured in various shapes. Oneshape that may be used is configured in disk form, with a diameter of 2to 3 cm, and a thickness of 2-4 mm. Other shapes that could be usedinclude egg-shaped, spherical or semi-spherical, rectangular withrounded corners, key-shaped, and the like. Whatever the shape, once theEA device is implanted, the housing of the EA device, with itsparticular shape, helps anchor the device, and more importantly helpsanchor its electrodes, in their desired position at or near the targetacupoint that is to be stimulated.

A preferred application for an EA device made in accordance with theteachings presented herein is to treat mental illnesses. Moreparticularly, the EA device and its method of use disclosed herein isdesigned to treat the following mental illnesses: major depressiondisorder (MDD), generalized anxiety disorder (Anxiety), bipolardisorder, post-traumatic stress disorder (PTSD), schizophrenia, andobsessive compulsive disorder (OCD). Thus, the description that followsdescribes in much more detail an EA device that is especially suited tobe used to treat mental illness. However, it is to be understood thatthe invention is not limited to treating mental illness. As explained inmore detail below, the essence of the invention recognizes that anelectroacupunture modulation scheme need not be continuous, therebyallowing the implanted EA device to use a small, high density, powersource to provide such non-continuous EA modulation. (Here, it should benoted that “EA modulation,” as that phrase is used herein, is theapplication of electrical stimulation pulses, at low intensities, lowfrequencies and low duty cycles, to at least one of the acupuncturesites that has been identified as affecting a particular illness,deficiency, disorder or condition.) As a result, the EA device can bevery small. And, because the electrodes form an integral part of thehousing of the EA device, or are connected thereto through a very shortlead, the EA device may thus be implanted directly at (or very near to)the desired target tissue location, e.g., the target acupoint. Hence,any condition of a patient that has heretofore been successfully treatedthrough conventional acupuncture treatments is a potential candidate fortreatment with the EA device described herein.

Modulation (i.e., EA stimulation) regimens, of course, may need to betailored to the specific illness, condition, disorder or deficiencybeing treated, but the same basic approach may be followed as is taughtherein for whatever acupoint is to be modulated. In summary, and asexplained more fully below in conjunction with the description of thetreatment of MDD, Anxiety, bipolar disorder, PTSD, schizophrenia, andOCD, the basic approach of EA stimulation includes: (1) identify anacupoint(s) that may be used to treat or mediate the particular illness,condition or deficiency that has manifest itself in the patient; (2)implant an EA device, made as described herein, so that its electrodesare firmly anchored and located so as to be near or on the identifiedacupoint(s); (3) apply EA modulation, having a low intensity, lowfrequency, and low duty cycle through the electrode(s) of the EA deviceso that electrical stimulation pulses flow through the tissue at thetarget acupoint(s) following a prescribed stimulation regimen overseveral weeks or months or years. At any time during this EA stimulationregimen, the patient's illness, condition or deficiency may be evaluatedand, as necessary, the parameters of the EA modulation applied duringthe EA stimulation regimen may be adjusted or “tweaked” in order toimprove the results obtained from the EA modulation.

Conditions Treated

Major depression and bipolar disorder are commonly categorized as moodor affective disorders. Persons with major depression are characterizedas having persistent low or sad mood, decreased or absent interest inalmost all activities, loss of self-confidence, and a feeling ofworthlessness. Most people with bipolar disorder (previously called“manic depressive” illness) experience alternating episodes of bothdepression and mania. Mania, which may be characterized as the oppositeof depression or a “high,” consists of an elated or elevated mood,increased activity, an overblown self-image, and an exaggerated sense ofself-confidence. Usually both depression and bipolar disorder areepisodic.

Additionally, persons with a primary diagnosis of mental illness otherthan major depression generally experience depression as a part of thecondition. Several of those mental illnesses may be appropriatelytreated by the EA device described herein, and the methods of using suchEA device, are focused on the following conditions:

(1) major depression disorder (“MDD”);

(2) generalized anxiety disorder (“Anxiety”);

(3) bipolar disorder

(4) post-traumatic stress disorder (“PTSD”)

(5) schizophrenia; and

(6) obsessive compulsive disorder (“OCD”).

Each of these six conditions is described in more detail in theparagraphs that follow.

The first of the mental illnesses treated by the device and methodsdescribed herein is major depression. Major depression, as characterizedpreviously in more detail, is described generally as showing symptoms oflow mood, from mild feelings of sadness to overwhelming feelings ofworthlessness. When people become depressed chemical changes are seen inthe brain, and researchers believe these changes are linked to thesymptoms of mood disorders. Imbalances in three monoamineneurotransmitters—serotonin, norepinephrine, and dopamine—are thought tocontribute to depression and bipolar disorder.

Studies on the mechanism of acupuncture for depression have been carriedout with respect to some central neurotransmitters,Hypothalamus-pituitary-adrenal (HPA) axis, immune system, limbic systemincluding the hippocampus and amygdala as well as the anterior thalamicnuclei and limbic cortex, and the signal transduction system in thenerve cell. See e.g., Liu Q, Yu J. Beneficial Effect of Acupuncture onDepression. Acupuncture Therapy for Neurological Diseases. Springer.2010; 437-39 (hereafter, “Liu 2010”). These studies have made someprogress in understanding the mechanism of acupuncture for depressionbut the complete mechanism requires further investigation.

In a study performed by Han et al., electroacupuncture was performed atGV20 and EXHN3 among several other points (the selection of whichdepended upon the type of depression diagnosed according to traditionalchinese medicine). The levels of cortisol content and endothelin-1content were decreased to normal levels after EA. See, Han C, Li X, LuoH, Zho X, Li X. Clinical Study on Electro-acupuncture Treatment for 30Cases of Mental Depression. J Tradit Chin Med 2004; 24(3): 172-6(hereafter, “Han 2004”). Additionally, the condition of depression inthose patients treated with EA was improved; treated patients with anaverage baseline score on the Hamilton Rating Scale for Depression(HRSD) of 30.15 were found to have scores on average of 11.73 after sixweeks of treatment.

Another theory is that electroacupuncture is able to release monoaminesin the central nervous system while depressed patients generally exhibitreduced metabolism of monoamine neurotransmitters. Biochemical studiesof some depressed patients who participated in an electroacupuncturestudy done by Meng et al. showed that their plasma norepinephrine levelchanged greatly after EA treatment. See, Meng F, Luo H, Shen Y, Shu L,Liu J. Plasma NE Concentrations and 24 Hours Urinary MHPG SO₄ ExcretionChanges After Electro-Acupuncture Treatment in Endogenous Depression.World J. Acup-Mox. 1994; 4:45-52 (hereafter, “Meng 1994”). It issuggested that the therapeutic effect of electroacupuncture at GV20 andEXHN3 is found by acting on the metabolic mechanism of norepinephrine inthe central nervous system. See, e.g. Meng 1994.

In addition to the regulation of norepinephrine levels in the brain, EAmay improve depression by its balancing of serotonin (along withnorepinephrine) levels in the brain. In a study conducted by Jin et al.,the mechanism of electroacupuncture of the acupoints GV20 and EXHN3 wasstudied in rats. See, Jin G L, Zhou D F, Su J. The effect ofelectro-acupuncture on chronic stress-induced depression rat brain'smonoamine neurotransmitters. Chin J. Psychiatry. 1999; 32: 220-222(hereafter, “Jin 1999”). In the male Sprague-Dawley rats, four groupswere created: a control group, a depression model, a depression modelwhere EA was applied, and a depression model with the use of the drugamitriptyline. In the depression model, the serotonin receptors orserotonin metabolite (“5-Hydroxytryptamine (5-HT)” or“5-Hydroxyindoleacetic acid (5-HIAA)”, respectively) in the cortex andthe metabolite of the neurotransmitter dopamine(“DA/3,4-dihydroxyphenylacetic acid (DOPAC)”) in the striatum were shownto be significantly lower than those in the control group. After EAtreatment, 5-HT/5-HIAA and norepinephrine (NE)/5-HT in the cortexreturned to normal level, and the decrease in the DA/DOPAC in thestriatum was not affected by EA. Thus, it appears that the stimulationat GV20 and EXHN3 could increase the activity of the 5-HT-type neuron bydecreasing the 5-HT metabolism in the cortex, which could rebuild thebalance of NE and 5-HT and produce a potential antidepressant effect.

Thus, while the mechanism of action is not well understood, there issignificant evidence that both symptoms and scales of depression may beimproved by electroacupuncture and that certain neurotransmitters arelikely involved.

Locations Stimulated and Stimulation Paradigms/Regimens

For treating any of the six mental illnesses previously described—MDD,Anxiety, bipolar disorder, PTSD, schizophrenia, or OCD—the preferredacupoints that need to be stimulated by the EA device, i.e., thepreferred target tissue locations at which electrical stimulation shouldbe applied in accordance with a specified stimulation regimen include atleast one target tissue location selected from the following group oftarget tissue locations:

-   -   1. Acupoint EXHN3 (Yintang) [Trigeminal nerve];    -   2. Acupoint GV20 (Baihui) [occipital and Trigeminal nerves];    -   3. The nerves underlying acupoints EXHN3 or GV20 (shown in        brackets above); and    -   4. The Three Branches of the Trigeminal nerve: the        supratrochlear, the supraorbital and the infraorbital.

The location of the above acupoints may be summarized as: EXHN3 on theforehead at the midpoint between the two medial ends of the eyebrow;and, GV20 on the head at the midpoint of the connecting line between theauricular apices. It is also about 4.5 inches superior to the anteriorhairline on the anterior median line. The location of acupoint GV20 isillustrated in FIG. 1B and is further illustrated on pages 203 and 213of WHO Standard Acupuncture Point Locations 2008, previouslyincorporated herein by reference. Selected portions of WHO StandardAcupuncture Point Locations 2008, including pages 203 and 213 areincluded in Appendix D, as are three pages from another reference,Quirico P E, Pedrali T. Teaching Atlas of Acupuncture, Volume 1:Channels and Points. Georg Thieme Verlag. 2007; pages 184, 186 and 190,which pages further illustrate the location of acupoint GV20 and EXHN3.Pages 180 through 196 of the Teaching Atlas of Acupuncture book byQuirico and Pedrali are incorporated herein by reference.

The acupoint, Baihui, is also designated by DU20 and GV20. Both “GV” and“DU” stand for the Governing Vessel meridian. It might also be calledGoverning Vessel 20.

Yintang is designated by EXHN3. “EX” stands for extra or extraordinarywhile “H N” stands for head and neck. Yintang has also been described asGV24.5, probably to describe the point as lying between acupoints GV24and GV25 since EX points were not named until much later in acupuncturehistory. Like all acupoints, the letters designating Baihui and Yintangare often spaced differently depending upon the source. For example,EXHN3 is the same as EX-HN3, which is the same as EX-HN-3.

Note, also, that Yintang or EXHN3 is also sometimes referred to as“Glabella.”

The acupoint EXHN3 may have other names since its discovery was late inacupuncture history.

In some instances, it will be advantageous to stimulate a plurality (twoor more) of acupoints together, i.e., implant a plurality of EA devices.For example, the acupoints EXHN3 and GV20 appear to be a goodcandidate-pair for treating bipolar disorder with a plurality of EAdevices, one at each acupoint.

In addition to the two disclosed acupoints for treatment of theaforementioned mental illnesses, three branches of the Trigeminal nerveare herein disclosed as stimulation targets: the supratrochlear, thesupraorbital, and the infraorbital (as indicated previously, these threebranches of the Trigeminal nerve are referred to herein as the “ThreeBranches” of the Trigeminal nerve).

One nerve that provides “a high-bandwidth pathway into the brain,”[quote attributed to Dr. Ian A. Cook, of the Semel Institute forNeuroscience and Human Behavior at UCLA, Los Angeles, Calif.], and whichis the nerve (or its branches) used by some of the devices, methods andsystems disclosed in this patent application to treat depression, is theTrigeminal nerve. The Trigeminal nerve is the fifth of 12 pairs ofcranial nerves in the head. It is the nerve responsible for providingsensation to the face. One Trigeminal nerve runs to the right side ofthe head and the other to the left. Each of these nerves has threedistinct branches. (“Trigeminal” derives from the Latin word “tria,”which means three, and “geminus,” which means twin.) After theTrigeminal nerve leaves the brain and travels inside the skull, itdivides into three smaller branches, controlling sensations throughoutthe face.

The first branch of the Trigeminal nerve controls sensation in the eye,upper eyelid and forehead and is referred to as the “Opthalmic Nerve” orV1. The Supraorbital nerve is a part of this branch.

The second branch of the Trigeminal nerve controls sensation in thelower eyelid, cheek, nostril, upper lip and upper gum and is called the“Maxillary Nerve” or V2. Two prominent branches of the Maxillary nerveare the Zygomatic nerve and the Infraorbital nerve.

The third branch of the Trigeminal nerve controls sensations in the jaw,lower lip, lower gum and some of the muscles used for chewing. Thisthird branch is called the “Mandibular Nerve” or V3.

The supraorbital nerve is a branch of the ophthalmic nerve (V). Thesupraorbital nerve courses from the forehead through the supraorbitalnotch (foramen) to join the supratrochlear nerve. The supratrochlearnerve carries information from the medial forehead, medial portion ofthe upper eyelid, and bridge of the nose.

Operation of the EA device is simple and straightforward. Once implantedand activated, electrical stimulation pulses are applied to the desiredacupoint at a low intensity, low frequency and low duty cycle inaccordance with a pre-programmed stimulation regimen. Because thestimulation is done at low intensities (amplitudes), low frequencies,and low duty cycles, the power source employed in the implantable EAdevice can also be very small, and can operate for long periods withoutneeding to be replaced, recharged or replenished.

There are two kinds of stimulation paradigms contemplated: a constantlow-frequency and low-amplitude paradigm, and a varied low-frequency andlow amplitude paradigm.

The constant frequency paradigm consists of low-frequency, constantstimulation at GV20, and/or EXHN3, and/or the trigeminal nerve at one ormore of three branches (supraorbital, infraorbital, and supratrochlear).The duration of a stimulation session should last as short as about 30minutes and as long as about seventy minutes. The time betweenstimulation sessions (or the rate of occurrence of the stimulationsession) should be as short as twenty-four hours and as long as twoweeks. The amplitude of stimulation should be as low as 2 mA and as highas 10 mA. The frequency of stimulation should be as low as 1 Hz and ashigh as 3 Hz.

The varied frequency paradigm contemplates a similar rate of occurrence,duration of stimulation, and amplitude of stimulation. The frequency,however, is not constant. The frequency may vary from 5 Hz to 15 Hz withseveral different frequencies applied during any session. The durationof a stimulation session is about 45 minutes but may be as short asabout 30 minutes and as long as about one hour. For example, astimulation regimen that fits the stimulation paradigm is: 10 minutes at12 Hz, then 10 minutes at 10 Hz, then 10 minutes at 8 Hz, then 15minutes at 6 Hz for a total duration of 45 minutes. The amplitude at allfrequencies is between 2 mA and 10 mA. Like the constant paradigm, therate of occurrence for the varied paradigm is as infrequently as onceevery two weeks and as frequently as twice daily.

In a study conducted by Han et al., patients were treated with what thegroup calls “computer controlled electroacupuncture” or “CCEA”. EA wasperformed at the main points EXHN3 and GV20 and in some patients, someacupoints on the limbs were also used and high-frequency EA was employedon those limb points. The application of CCEA with a stimulationparadigm similar to the one disclosed here successfully improveddepression. See e.g., Han C, Li X, Luo H. Randomized Clinical TrialComparing the Effects of Electro-acupuncture and Maprotiline in TreatingDepression. Int J Clin Acupunct 2006; 15(1): 7-14 (hereafter, “Han2006”). See also, Luo H, Shen Y, Meng F, Jia Y, Zhao X, Guo H, Feng X.Preliminary Research on Treatment of Common Mental Disorders withComputer Controlled Electroacupuncture. Chin J Integr Med 1996; 2(2):98-100 (hereafter, “Luo 1996”).

Support for Selected Acupoints/Target Tissue

Various studies and research have provided support for using one or moreof these particular two acupoints for the treatment of mental illness. Asummary of some of these studies and research is presented in theparagraphs that follow and studies specific to particular mentalillnesses are specified.

The acupoints GV20 and EXHN3 have been selected because they areassociated with increases in serotonin suggesting a beneficialapplication in depression. See, e.g., Luo H C, Jia Y K, Li Z.Electro-acupuncture vs. amitriptyline in the treatment of depressivestates. J Tradit Chin Med 1985; 5:3-8 (hereafter, “Luo 1985”).

Additionally, in a selection of work performed by Dr. Luo Hechun et al.,both manual acupuncture and electroacupuncture of these two points havebrought about positive results in depression—results showing efficacyequal to that seen in drugs such as the tetracyclic maprotiline and thetricyclic antidepressant amitriptyline. See, e.g., Luo H, Meng F, Jia Y,Zhao X. Clinical research on the therapeutic effect of theelectro-acupuncture treatment in patients with depression. PsychiatryClin Neurosci 1998; 52 Suppl:S338-S340 (hereafter, “Luo 1998”); Han2004; Han 2006.

In an abstract published in English in 2003, EA at EXHN3 and GV20 wasshown to improve depression as a whole based upon the Hamilton RatingScale for Depression (HRSD) which also measures Anxiety. When comparedto the anti-anxiety medication fluoxetine (commonly known by the brand“Prozac”), more improvement was seen in the EA group. See, Luo H, UreilH, Shen Y. Comparative study of electroacupuncture and fluoxetine fortreatment of depression. Chin J Psychiatry, 2003; 36(4): 215. Chinesewith English abstract (hereafter, “Luo 2003”).

In studies done by Luo et al in patients with depression where EA iscompared with antidepressants, EA proves to do better than the drug inthe improvement of Anxiety. See, e.g., Luo 1985; Clinical research onthe therapeutic effect of the electro-acupuncture treatment in patientswith depression. Psychiatry Clin Neurosci 1998; 52 Suppl:S338-S340(hereafter, “Luo 1998”).

In particular, in two studies conducted by Han et al, EA is shown toimprove Anxiety levels better than the drug maprotiline, which is usedto treat depression. See, Han 2006; Han C, Li X W, Luo H C. Comparativestudy of electro-acupuncture and maprotiline in treating depression.Zhongguo Zhong Xi Yi Jie He Za Zhi. 2002; 22(7): 512-514. Chinese withEnglish Abstract (hereafter, “Han 2002”).

Since serotonin and norepinephrine (along with gamma-aminobutyric acidor “GABA” and dopamine) are implicated in Anxiety, studies showing thatEA changes levels of serotonin and norepinephrine in the brain suggestpositive evidence for the treatment of Anxiety. See e.g., Jin 1999; Luo1998.

Medications for the treatment of Anxiety disorders are available in sixdifferent classes: benzodiazepines, buspirone, selective serotoninreuptake inhibitors (SSRIs), serotonin and norepinephrine reuptakeinhibitors (SNRIs), tetracylics, and tricyclics. See, Swartz 2011. Fiveof the six classes (all excluding benzodiazepines for which themechanism is unclear) involve the regulation of serotonin ornorepinephrine—the neurotransmitters that are implicated in mechanismstudies related to the present invention. Given that EA seems to do evenbetter than two antidepressants and in particular, better than an SSRIfluoxetine indicated for Anxiety, the disclosed invention should provesuccessful to reduce anxiety in Anxiety disorders.

The existence of low levels of norepinephrine are thought to be involvedin bipolar disorder. Thus, evidence that acupuncture or EA at theselected points increases norepinephrine in depression models may beevidence for the successful treatment of bipolar disorder. See, e.g.Meng 1994; Jin 1999.

Similarly, decreased levels of serotonin are often found in people withbipolar disorder and depression. Since the serotonin receptors 5-HT wereincreased after EA, EA at the relevant acupoints may also improvebipolar disorder by way of the changes in levels of serotonin. See, Jin1999.

Additionally, in at least three trials performing electroacupuncture atGV20 and EXHN3 and lead by Luo, bipolar patients were included among thedepressed patients. See, Luo H, Shen Y, Meng F, Jia Y, Zhao X, Guo H,Feng X. Preliminary Research on Treatment of Common Mental Disorderswith Computer Controlled Electroacupuncture. Chin J Integr Med 1996;2(2): 98-100 (hereafter, “Luo 1996”); Luo H, Jia Y, Wu X, Dai W.Electro-acupuncture in the treatment of depressive psychosis. Int J ClinAcupunct 1990; 1(1):7-13; Luo H, Meng F, Jia Y, Zhao X. Chinese withEnglish abstract. (hereafter, Luo 1990); Luo 1998; Han 2006.

Bipolar disorder requires lifelong treatment that generally starts withmedication. There are seven classes of medications used to treat bipolardisorder—and medications within three of the classes are also approvedby the FDA to treat major depression. Those medications used to treatboth major depression and bipolar disorder are: Abilify (aripiprazole),Risperdal (risperidone), Symbax (olanzapine/fluoxetine), andantidepressants as a whole. Symbyax, in particular, works by increasingthe availability of the neurotransmitters serotonin, norepinephrine, anddopamine to treat depression associated with bipolar disorder. See,Swartz 2011. Likewise, antidepressants are prescribed to treatdepression associated with bipolar disorder. The mechanism of action inthe present invention (and its involvement of serotonin andnorepinephrine) as previously described is similar to that known to beworking in the approved aforementioned drugs.

Treatment of post-traumatic stress disorder (PTSD) requires acombination of psychotherapy aimed at desensitizing the individual tothe traumatic experience and medication. There are only two medications,approved by the FDA for treatment of PTSD: Zoloft and Paxil. Both areselective serotonin reuptake inhibitors (SSRIs). The tricyclicsamitriptyline and Norpramin are also commonly used to treat the mooddisturbances and anxiety accompanying the disorder.

Since EA at EXHN3 and GV20 is shown to be just as efficacious or moreefficacious than antidepressant amitriptyline in the anxiety element ofAnxiety per the Hamilton Rating Scale for Depression (HRSD), it islikely the disclosed device may be efficacious in the Anxietyaccompanying PTSD as well. See, e.g., Luo 1985; Luo 1998. See also, Han2006; Han C, Li X W, Luo H C. Comparative study of electro-acupunctureand maprotiline in treating depression. Zhongguo Zhong Xi Yi Jie He ZaZhi. 2002; 22(7): 512-514. Chinese with English Abstract (hereafter,“Han 2002”).

Additionally, EA has been shown to affect the levels of serotonin in thebrain. See, Jin 1999. While few SSRIs are indicated for the treatment ofPTSD, EA's specific effect on the regulation of serotonin may similarlybenefit patients with PTSD.

It is thought that the negative symptoms of schizophrenia, i.e. flataffect and catatonia, involve the levels of serotonin in the brain.Newer antipsychotic drugs are aimed at blocking both dopamine receptorsand serotonin receptors to reduce the negative and positive symptoms ofschizophrenia. Thus, regulation of serotonin by EA may be beneficial tothe treatment of schizophrenia. See e.g., Jin 1999.

Schizophrenia has been treated with some success by EA at GV20 and EXHN3in at least one trial. See, Luo 1996. Both disease states, in additionto depression, have shown improvement in the condition fromelectroacupuncture. Thus, while the mechanism of action may not be fullydrawn out, it is expected that the present invention may be applicableto such disorders.

It is thought that the biochemical basis of obsessive compulsivedisorder (OCD) is an imbalance in the neurotransmitter serotonin. In OCDpatients, receptors are thought to block serotonin from entering thecell. This leads to a deficiency in key areas of the brain. The onlymedications that are effective in treating OCD are antidepressants thatinteract with the chemical serotonin. Five antidepressants are approvedby the FDA to treat OCD: Anafranil, Luvox, Prozac, Paxil, and Zoloft.Four of those antidepressants (Luvox, Prozac, Paxil, and Zoloft) areclassified as selective serotonin reuptake inhibitors (SSRIs). Anafranilis classified as a serotonin reuptake inhibitor (SRI). Celexa, also anSSRI, is also used to treat OCD without FDA approval. The same drugsapproved to treat OCD are used and approved to treat depression,anxiety, and OCD by stopping nerve cells that have just releasedserotonin from absorbing it back into the cell and making it readilyavailable for other neurons. Thus, the treatment of OCD with medicationand its involvement of serotonin regulation is in line with themechanism of action described in EA, which is most similar to thepresent invention. See e.g., Jin 1999. Additionally, EA, like the drugAnafranil, likely modulates norepinephrine as well as serotonin. Seee.g., Meng F, Luo H, Shen Y, Shu L, Liu J. Plasma NE Concentrations and24 Hours Urinary MHPG SO₄ Excretion Changes After Electro-AcupunctureTreatment in Endogenous Depression. World J. Acup-Mox. 1994; 4:45-52(hereafter, “Meng 1994”). Note that all medications approved to treatOCD are also considered medications to treat Anxiety, a condition forwhich EA is particularly efficacious (as previously described).

In a study conducted by Wang et al, electroacupuncture at GV20 and EXHN3demonstrated positive results in what the group called “neurosis,” whichvery likely includes the condition of OCD. About 64% of patients withneurosis were improved by electroacupuncture at these points and all ofwhom who were not improved did not undergo more than 60 sessions ofelectroacupuncture. See, e.g. Wang H, Yu E, Zhao J. Clinical Analysis ofCommon Psychosis Treated by Electroacupuncture in 129 Cases. Journal ofClinical Acupuncture and Moxibusion. 1999; (1):42 (hereafter, “Wang1999”). For a study on the use of varying frequency to treat “neurosis”,see also, Luo H, Shen Y, Meng F, Jia Y, Zhao X, Guo H, Feng X.Preliminary Research on Treatment of Common Mental Disorders withComputer Controlled Electroacupuncture. Chin J Integr Med 1996; 2(2):98-100 (hereafter, “Luo 1996”).

To facilitate an understanding of the methods and systems describedherein, an exemplary EA System will next be described in two sections,Section I and Section II. Section I will describe the invention inconnection with the detailed description of FIGS. 17-31, which relate togeneral principles and concepts associated with the invention. SectionII will then provide, in detail, a specific example of the invention inconnection with the description of FIGS. 1-16.

Stimulation of the supratrochlear and supraorbital branches of thetrigeminal nerve is also supported by studies supporting the treatmentof mental illness by electrical stimulation of EXHN3 since EXHN3 isinnervated by those branches. See, Chen E. Cross-Sectional Anatomy ofAcupoints. Churchill Livingstone. 1995. P114 (hereafter, “Chen,Cross-Sectional Anatomy of Acupoints, 1995”).

In a recent proof of concept study conducted by physicians at UCLA'sDavid Geffen School of Medicine, transcutaneous electrical nervestimulation (TENS) of the trigeminal nerve was done in patients withmajor depressive disorder with success. See, Shrader L, Cook P, MaremontE, DeGiorgio C. Trigeminal nerve stimulation in major depressivedisorder: First proof of concept in an open pilot trial. Epilepsy Behav2011; 22:475-8 (hereafter, “Shrader 2011”). See also, DeGiorgio C,Fanselow E, Shrader L, Cook I. Trigeminal Nerve Stimulation: SeminalAnimal and Human Studies for Epilepsy and Depression. Neurosurg Clin NAm 2011; 22:449-456 (hereafter, “DeGiorgio 2011”). While TENS produces adiffuse stimulation field different from the one contemplated in thepresent invention and the stimulation regime is quite different fromthat in the present invention (i.e. it is high frequency and applied for8 hours at a time), the stimulation of the trigeminal nerve at thesupraorbital and infraorbital branch is achieved and depressionimproved.

I. General Principles and Concepts

An exemplary EA System 10 will next be described in connection withFIGS. 18-31. First, with respect to FIG. 18, and subsequently withrespect to other figures which show, and the accompanying descriptiondescribes, more details and features associated with the EA System 10are illustrated and described. As has already been indicated, apreferred application of the EA System is to treat mental illness, e.g.,MDD, Anxiety, bipolar disorder, PTSD, schizophrenia, and OCD. But, ashas also previously been indicated, the EA System has applicability totreating other conditions, illnesses, disorders and deficiencies otherthan just mental illnesses. The scope of the invention should beascertained from the claims.

As seen in FIG. 18, the EA System 10 includes two main components: (1)an External Control Device (ECD) 20 and (2) an ImplantableElectroAcupuncture Device 30, or IEAD 30. (It is noted that in SectionII below, the IEAD is also referred to using the reference numeral 100.Thus, whether it is referred to as the IEAD 30 or the IEAD 100, it isessentially the same or a similar element.) Two versions of the ECD 20are included in FIG. 18. A first is a hand-held electronic device thatincludes a port 211 enabling it to be coupled to a computer, or similarprocessor. A second is a magnet, typically a cylindrical magnet. Twoversions of an IEAD are also included in FIG. 18, either one of whichmay be used. One embodiment (top right of FIG. 17) has an electrode 32that forms an integral part of the case 31 of the IEAD 30; and the otherembodiment (lower right of FIG. 1A) has an electrode 32 that is locatedat the end of a short lead 41 attached to the IEAD 30.

The IEAD 30, in one embodiment, is disc shaped, having a diameter ofabout 2 to 3 cm, and a thickness of about 2 to 4 mm. It is implantedjust under the skin 12 of a patient near a desired acupuncture site.Other shapes and sizes for the IEAD 30 may also be used, as described inmore detail below. The desired acupuncture site is also referred toherein as a desired or target “acupoint.” For MDD, Anxiety, bipolardisorder, PTSD, schizophrenia, and OCD, the acupoints and nerve ofinterest include EXHN3 (“Yintang” or sometimes, “Glabella”), GV20(“Baihui” or sometimes designated by “DU20”), and the trigeminal nerveincluding the infraorbital, supraorbital, and supratrochlear branches.

The IEAD 30 includes an electrode 32 which may take various forms. Atleast a portion of the electrode, in some embodiments, may include arod-like body and a pointed or tapered tip, thereby resembling a needle.Because of this needle-like shape, and because the electrode 32 replacesthe needle used during conventional acupuncture therapy, the electrode32 may also be referred to herein as a “needle electrode”. However, analternate and preferred electrode form to replace a “needle electrode”is a smooth surface electrode, without any sharp or pointed edges.

For the embodiment shown in the top right portion of FIG. 18, and forthe IEAD 30, the electrode 32 forms an integral part of the housing 31of the IEAD 30, and is located on a “front” side of the IEAD housingapproximately in the center of the housing. As used here, “front” meansthe side of the housing that fronts or faces the tissue to bestimulated. Frequently, but not always, the front side is the side ofthe IEAD housing 31 farthest from the skin layer 12, or deepest in thebody tissue. Other embodiments may incorporate an electrode that is notcentered in the housing 31, and that is not even on the front side ofthe housing, but is rather on an edge of the housing 31. Alternatively,as shown in the bottom right of FIG. 18, the electrode 32 may be locatedat the distal end of a short lead 41, e.g., nominally 10-20 mm long, butin some instances it may be up to 50 mm long, implanted with a strainrelief loop to isolate movement of the case from the electrode. Theproximal end of the lead is attached to the IEAD 30 along an edge of theIEAD housing 31 or at a suitable connection point located on a side ofthe IEAD 30. Alternate configurations for attaching the proximal end ofthe lead 41 to the IEAD housing 31 are illustrated in Appendix F.

When implanted, the IEAD 30 is positioned such that the electrode 32resides near, directly over, or otherwise faces the target tissuelocation, e.g., the desired acupoint or nerve, that is to be stimulated.For those embodiments where the electrode 32 forms an integral part ofthe housing 31 of the IEAD 30, there is thus no need for a long leadthat must be tunneled through body tissue or blood vessels in order toplace the electrode at the desired acupoint or nerve. Moreover, even forthose embodiments where a very short lead may be employed between theIEAD 30 and the electrode 32, the tunneling required, if any, is ordersof magnitude less than the present state of the art. In fact, with anelectrode lead of between 20 mm and 50 mm in length, it is probable thatno tunneling will be required. Further, because the electrode eitherforms an integral part of the IEAD housing 31, or is attached to theIEAD housing a very short pigtail lead, the entire IEAD housing 31serves as an anchor to hold or secure the electrode 32 in its desiredlocation.

For the embodiment depicted in the top right of FIG. 18 and as mentionedabove, the electrode 32 is located in the center of the front side ofthe IEAD 30. As explained in more detail below, this positioning of theelectrode 32 is only exemplary, as various types of electrodes may beemployed, as well as various numbers of electrodes and relativepositioning. See, e.g., FIGS. 20 through 21C, and accompanying text,presented below. See also, Appendix A and Appendix B.

Still referring to FIG. 18, the EA System 10 also includes an externalcontrol unit, or ECD, 20. The role that the ECD 20 plays in theoperation of the EA system varies as a function of which embodiment ofthe EA System is being used. A USB port 211, located on one side of theECD, allows it to be connected to a PC or notebook computer or othersuitable processor for diagnostic, testing, or programming purposes.Other ports or connectors may also be used on the ECD 20, as needed bythe various embodiments employed. In its simplest form, however, the ECD20 may take the form of a handheld magnet, described in more detailbelow in conjunction with a specific example of the invention.

FIG. 18A is a Table that highlights the main embodiments of the EASystem 10, and provides a summary description of the functions performedby the External Controller 20 and IEAD 30 in each embodiment. It isimportant to note that the list of embodiments identified in FIG. 18A isnot a complete list, but is only representative of four of the manyembodiments that could be employed. Thus, the embodiments highlighted inFIG. 18 include, but are not limited to:

Embodiment I

Embodiment I comprises a fully implantable EA System wherein the IEAD 30provides the desired stimulation as controlled by an internal program,or stimulation regime, programmed into its circuits. When thusconfigured, the External Controller 20 is used in Embodiment I only as aprogrammer to program the operating parameters of the IEAD 30. When theIEAD 30 is operating, all of its operating power is obtained from apower source carried within the IEAD 30.

Embodiment II

Embodiment II is essentially the same as Embodiment I except that theExternal Controller 20 is used, when needed, to both program the IEAD 30and to recharge or replenish a rechargeable and/or replenishable powersource carried within the IEAD 30.

Embodiment III

In Embodiment III, all or most all of the functions of the EA System areperformed within the External Controller 20 except for delivery of thedesired stimuli to the desired acupoint through the electrode 32. Hence,when the EA System operates using Embodiment III, the ExternalController 20 must always be present and RF-coupled ormagnetically-coupled to the IEAD 20. That is, in Embodiment III, theExternal Controller 20 generates the stimulation energy at the desiredtime, duration and intensity. Then, it sends, i.e., transmits, thisenergy through the skin 12 to the implantable electroacupuncturestimulator 30. Such transmission of energy through the skin is typicallydone through electromagnetic coupling, e.g., inductive coupling, muchlike a transformer couples energy from its primary coil to its secondarycoil. For coupling through the skin, the primary coil is located in theExternal Controller 20 and the secondary coil is located in the IEAD 30.The IEAD 30 receives this energy and simply passes it on to theelectrode 32 via interconnecting conductive traces or wires. EmbodimentIII is particularly useful for diagnostic and data-gathering purposes,but can also be used by a patient who does not mind occasionally wearingan external device positioned on his or her skin over the location wherethe IEAD is implanted whenever the EA System is operational.

Embodiment IV

In Embodiment IV, the EA system is a fully, self-contained, implantableIEAD except for the use of an external “passive” control element, suchas a magnet. The external control element is used to perform very basicfunctions associated with the IEAD, such as turning the IEAD OFF or ON,changing the intensity of stimulus pulses by a small amount, slightlymodifying the timing of stimulation sessions, resetting the parametersof the stimulation regimen back to default values, and the like.

Next, with reference to FIG. 19, there is shown an illustration orrepresentation of the human head. The illustration shows the location ofthe two acupoints selected by Applicant to be used for the treatment ofvarious mental illnesses disclosed in this patent application. Theseacupoints have been identified based on an analysis of successful andunsuccessful acupuncture studies for the treatment of depression. Fromsuch an analysis and from work laid out by Luo's group, Applicantidentified GV20 and EXHN3 as the primary acupoints involved whendepression is improved. See, e.g., Luo 1985; Luo 1990; Luo 1998; Han2004; Fu W B, Fan L, Zhu X P, He Q, Wang L, Zhuang L X, Liu Y S, Tang CZ, Li Y W, Meng C R, Zhang H L, Yan J. [Acupuncture for treatment ofdepressive neurosis: a multi-center randomized controlled study] 2008.Zhongguo Zhen Jiu (Chinese Acupuncture & Moxibustion) 28(1):3-6. Chinesewith English abstract; Luo H C, Shen Y C, Jia Y K. [Clinical study ofelectroacupuncture on 133 patients with depression in comparison withtricyclic amitriptyline]. Zhong Xi Yi Jie He Za Zhi 1988; 8(2):77-80.Chinese with English Abstract. The illustration shows these chosenacupoints. Further illustrations of the location of acupoints EXHN3 andGV20 are provided in FIGS. 1A and 1B, as well as in Appendix D.

A preferred stimulation regimen for use with the selected acupointsstimulates the selected target acupoint over several months or years,but at a very low duty cycle, e.g., applying a stimulation session thathas a duration of 30 to 60 minutes only once or twice a week. Forpurposes of the present invention, Applicant has determined that if astimulation session has a duration of T3 minutes, and if the timebetween stimulation sessions is T4 minutes, the duty cycle, or ratio ofT3/T4, should be no greater than 0.05.

In some instances, and for some patients, it may be desirable to invokea stimulation session of about one hour each day. For other patients,the stimulation session may only need to be invoked one hour every week,or every other week. In either event, the duty cycle (the ratio ofT3/T4) still remains low, less than 0.05.

One advantage of providing stimulation pulses using a low duty cycle, asdescribed above, is that the power source of the IEAD 30 is able topower operation of the IEAS over long periods of time. Through carefulpower management, detailed more fully below in conjunction with thedescription of a specific example, the IEAD 30 may operate for severalyears.

Alternatively, in some embodiments of the invention, the power sourcecarried in the EA device may be recharged or replenished in 20 to 30minutes or less, thus providing additional operating power for the EAdevice in the event stimulation sessions are desired more often that canbe supported by a duty cycle of 0.05 or less.

Turning next to FIGS. 20, 20A and 20B, a mechanical drawing of oneembodiment of the housing 31 of the implantable electroacupuncturestimulator 30 is illustrated, along with various types of electrodesthat may be used therewith. In a first embodiment, as seen in FIG. 20,the housing 31 of the IEAD 30 is preferably disc-shaped, having adiameter “d1” and width “w1”. The housing 31 is made from a suitablebody-tissue-compatible (biocompatible) metal, such as Titanium orstainless steel, having a thickness of 0.2 to 1.0 mm. An electrode 32resides at the center of the front side of the housing 31. The frontside of the housing 31 is the side facing out of the paper in FIG. 20,and is the side faces the target tissue to be stimulated. Most often,this is the side that is farthest away from the surface of the skin whenthe stimulator device is implanted in a patient. Thus, the front side isalso sometimes referred to as the “underneath” side of the device.

The electrode 32 is surrounded by a ceramic or glass section 34 thatelectrically insulates the electrode 32 from the rest of the housing 31.This ceramic or glass 34 is firmly bonded (brazed) to the metal of thehousing 31 to form an hermetic seal. Similarly, a proximal end 35 of theelectrode 34, best seen in the sectional views of FIG. 20A or 20B,passes through the ceramic or glass 34, also forming an hermetic seal.The resultant structure resembles a typical feed-through pin commonlyused in many implantable medical devices, and allows electricalconnection to occur between electrical circuitry housed within thehermetically-sealed housing and body tissue located outside of thehermetically-sealed housing.

In the embodiment of the housing 31 shown in FIGS. 20, 20A and 20B, theelectrode 32 is shown formed to have a narrow tip, much like a needle.Hence, the electrode 32 is sometimes referred to as a needle electrode.It is commonly taught that a needle electrode of this type generallyallows the electric fields associated with having a current flowing outof or into the needle tip to be more sharply focused, and thereby allowsthe resultant current flow through the body tissue to also be moresharply focused. This helps the electrical stimulation to be appliedmore precisely at the desired acupuncture point. Further, because mostacupoints tend to exhibit a lower resistance than do non-acupoints, theamount of power required to direct a stimulation current through theacupoint is lower, thereby helping to conserve power.

However, as will be explained in more detail below in conjunction withApplicant's specific example (Section II), Applicant's preferredelectrode shape is smooth, and symmetrical, which shape andconfiguration allow the resultant electric fields to deeply penetrateinto the desired target tissue.

As is known in the art, all electrical stimulation requires at least twoelectrodes, one for directing, or sourcing, the stimulating current intobody tissue, and one for receiving the current back into the electroniccircuitry. The electrode that receives the current back into theelectronic circuit is often referred to as a “return” or “ground”electrode. The metal housing 31 of the IEAD 30 may function as a returnelectrode during operation of the IEAD 30.

FIG. 20A is a sectional view, taken along the line A-A of FIG. 20, thatshows one embodiment of the IEAD housing wherein the needle electrode 32resides in a cavity 37 formed within the front side of the IEAD housing31.

FIG. 20B is a sectional view, taken along the line A-A of FIG. 20, andshows an alternative embodiment of the front side of the IEAD whereinthe needle or other electrode 32 forms a bump that protrudes out fromthe front surface of the IEAD a short distance.

FIG. 20C is a sectional view, taken along the line A-A of FIG. 20, andshows yet another alternative embodiment where a short lead 41, having alength L1, extends out from the housing 31. The electrode 32, which maybe formed in many shapes, is located at a distal end of the lead 41. Theshapes of the electrode, for example, may be a ball, cone or taperedcylindrical, ring, bullet shaped or full or half cuffed, with electrodeanchoring features. See, e.g., Appendix F, where various shapedelectrodes at the end of a short pigtail lead are illustrated. Thelength L1 of this short electrode is nominally 10-20 cm, but may extendas long as 50 mm. A proximal end of the lead 41 attaches to the housing31 of the IEAD 30 through a feed-through type structure made of metal 35and glass (or ceramic) 34, as is known in the art.

Next, with reference to FIGS. 21, 21A, 21B, and 21C, there is shown anembodiment of the IEAD 30 that shows the use of four needle electrodesintegrated within the housing 31 of an IEAD 30. The needle electrodes 32have a tip 33 that protrudes away from the surface of the housing 31 ashort distance. A base, or proximal, portion of the needle electrodes 32is embedded in surrounding glass or ceramic 34 so as to form an hermeticbond between the metal and ceramic. A proximal end 35 of the needleelectrode 32 extends into the housing 31 so that electrical contact maybe made therewith. The ceramic or glass 34 likewise forms a metallicbond with the edge of the housing 31, again forming an hermetic bond.Thus, the needle electrodes 32 and ceramic 34 and metal housing 31function much the same as a feed-through pin in a conventionalimplantable medical device housing, as is known in the art. Suchfeed-through pin allows an electrical connection to be establishedbetween electrical circuitry housed within the hermetically-sealedhousing 31 and body tissue on the outside of the hermetically sealedhousing 31.

Having four needle electrodes arranged in a pattern as shown in FIG. 21allows a wide variation of electric fields to be created emanating fromthe tip 33 of each needle electrode 32 based on the magnitude of thecurrent or voltage applied to each electrode. That is, by controllingthe magnitude of the current or voltage at each tip 32 of the fourelectrodes, the resulting electric field can be steered to a desiredstimulation point, i.e., to the desired electroacupuncture (EA) point ornerve.

FIG. 21C is a also a sectional view, taken along the line B-B of FIG.21, that shows yet another embodiment of the EA device where theelectrodes comprise small conductive pads 47 at or near the distal endof a flex circuit cable 45 that extends out from the underneath surfaceof the IEAD a very short distance. To facilitate a view of the distalend of the flex circuit cable 45, the cable is shown twisted 90 degreesas it leaves the underneath surface of the IEAD 30. When implanted, theflex circuit cable 45 may or may not be twisted or have a strain reliefloop, depending upon the relative positions of the IEAD 30 and thetarget acupoint to be stimulated. As can be seen in FIG. 21C, at thedistal end of the flex circuit cable 45 the four electrodes 32 arearranged in a square pattern array. Other arrangements of the electrodes32 may also be employed, a linear array, a “T” array, and the like. Manyother alternate electrode configurations are illustrated, e.g., inAppendix A and Appendix B.

While only one or four electrodes 32 is/are shown as being part of thehousing 31 or at the end of a short lead or cable in FIGS. 20 and 21,respectively, these numbers of electrodes are only exemplary. Any numberof electrodes, e.g., from one to eight electrodes, that conveniently fiton the underneath or front side or edges of an IEAD housing 31, or on apaddle array (or other type of array) at the distal end of a short lead,may be used. The goal is to get at least one electrode (whether anactual electrode or a virtual electrode—created by combining theelectric fields emanating from the tips of two or more physicalelectrodes) as close as possible to the target EA point, or acupoint.When this is done, the EA stimulation should be more effective.

Next, with reference to FIGS. 22A through 22E, various alternate shapesof the housing 31 of the IEAD 30 that may be used with an EA System 10are illustrated. The view provided in these figures is a side sectionalview, with at least one electrode 32 also being shown in a sidesectional view. In FIGS. 22A through 22D, the electrode 32 iselectrically insulated from the housing 31 by a glass or ceramicinsulator 34. A portion of the electrode 32 passes through the insulator34 so that a proximal end 35 of the electrode 32 is available inside ofthe housing 31 for electrical contact with electronic circuitry that ishoused within the housing 31.

In FIG. 22A, the housing 31 is egg shaped (or oval shaped). A bump orneedle type electrode 32 protrudes a small distance out from the surfaceof the housing 31. While FIG. 22A shows this electrode located more orless in the middle of the surface of the egg-shaped housing, thispositioning is only exemplary. The electrode may be located anywhere onthe surface of the housing, including at the ends or tips of the housing(those locations having the smallest radius of curvature).

In FIG. 22B, the housing 31 of the IEAD 30 is spherical. Again, a bumpor needle-type electrode 32 protrudes out a small distance from thesurface of the housing 31 at a desired location on the surface of thespherical housing. The spherical housing is typically made by firstmaking two semi-spherical housings, or shells, and then bonding the twosemi-spherical housings together along a seam at the base of eachsemi-spherical shell. The electrode 32 may be located at some pointalong or near this seam.

In FIG. 22C, the housing 31 is semi-spherical, or dome shaped. A bump orneedle electrode 32 protrudes out from the housing at a desiredlocation, typically near an edge of the base of the semi-spherical ordome-shaped housing

In FIG. 22D, the housing is rectangular in shape and has rounded edgesand corners. A bump or needle electrode 32 protrudes out from thehousing at a desired location on the underneath side of the housing, oralong an edge of the housing. As shown in FIG. 22D, one location forpositioning the electrode 32 is on the underneath side near the edge ofthe housing.

In FIG. 22E, the housing 31 is key shaped, having a base portion 51 andan arm portion 53. FIG. 22E includes a perspective view “A” and a sidesectional view “B” of the key-shaped housing 31. As shown, the electrode32 may be positioned near the distal end of the arm portion 53 of thehousing 31. The width of the arm portion 53 may be tapered, and all thecorners of the housing 31 are rounded or slanted so as to avoid anysharp corners. The key-shaped housing shown in FIG. 22E, or variationsthereof, is provided so as to facilitate implantation of the IEAD 30through a small incision, starting by inserting the narrow tip of thearm portion 53, and then sliding the housing under the skin as requiredso that the electrode 32 ends up being positioned over, adjacent or onthe desired acupoint.

In lieu of the bump or needle-type electrodes 32 illustrated in FIGS.22A through 22C, a smooth, flat or other non-protruding electrode 32 mayalso be used.

It is to be noted that while the various housing shapes depicted inFIGS. 22A through 22E have a bump or needle-type electrode (and whichcould also be a flat or smooth electrode as noted in the previousparagraph) that form an integral part of the IEAD housing 31, electrodesat the distal end of a short lead connected to the IEAS housing may alsobe employed with any of these housing shapes.

It is also to be emphasized that other housing shapes could be employedfor the IEAD 30 other than those described. For example, reference ismade to the alternate case shapes shown in Appendix E. The inventiondescribed and claimed herein is not directed so much to a particularshape of the housing 31 of the IEAD 30, but rather to the fact that theIEAD 30 need not provide EA stimulation on a continuous basis, but mayoperate using a very low duty cycle, and therefore the power sourcecarried in the IEAD need not be very large, which in turn allows theIEAS housing 31 to be very small. The resulting small IEAD 30 may thenadvantageously be implanted directly at or near the desired acupoint,without the need for tunneling a lead and an electrode(s) over a longdistance, as is required using prior art implantable electroacupuncturedevices. Instead, the small IEAD 30 used with the present inventionapplies its low duty cycle, non-continuous EA stimulation regime at thedesired acupoint without the use of long leads and extensive tunneling,which stimulation regime applies low intensity, low frequency and lowduty cycle stimulation at the designated acupoint over a period ofseveral years in order to improve depression or a related mental illness(or whatever other condition, illness or deficiency is being treated).

Turning next to FIG. 23, an electrical functional block diagram of theelectrical circuitry and electrical components housed within the IEAD 30and the External Controller 20 is depicted. The functional circuitryshown to the right of FIG. 4 is what is typically housed within the IEAD30. The functional circuitry shown to the left of FIG. 4 is what istypically housed within the External Control Device 20, also referred toas an External Controller 20. How much circuitry is housed within theIEAD 30 and how much is housed within the External Controller 20 is afunction of which embodiment of the EA System 10 is being used.

It is to be noted and emphasized that the circuitry shown in FIG. 23,and in the other figures which show such circuitry, is intended to befunctional in nature. In practice, a person of skill in the electrical,bioelectrical and electronic arts can readily fashion actual circuitsthat will perform the intended functions. Such circuitry may berealized, e.g., using discrete components, application specificintegrated circuits (ASIC), microprocessor chips, gate arrays, or thelike.

As seen in FIG. 23, the components used and electrical functionsperformed within the IEAD 30 include, e.g., a power source 38, an outputstage 40, an antenna coil 42, a receiver/demodulator circuit 44, astimulation control circuit 46, and a reed switch 48. The componentsused and electrical functions performed with the External Controller 20include, e.g., a power source 22, a transmission coil 24, a centralprocessing unit (CPU) 26, a memory circuit 25, a modulator circuit 28and an oscillator circuit 27. The External Controller 20 also typicallyemploys some type of display device 210 to display to a user the statusor state of the External Controller 20. Further, an interface element212 may be provided that allows, e.g., a means for manual interface withthe Controller 210 to allow a user to program parameters, performdiagnostic tests, and the like. Typically, the user interface 212 mayinclude keys, buttons, switches or other means for allowing the user tomake and select operating parameters associated with use of the EASystem 10. Additionally, a USB port 211 is provided so that the ExternalController 20 may interface with another computer, e.g., a laptop ornotebook computer. Also, a charging port 213 (which may also be in theform of a USB port) allows the power source 22 within the ExternalController 20 to be recharged or replenished, as needed.

In operation, the Stimulation Control Circuit 46 within the IEAD 30 hasoperating parameters stored therein that, in combination withappropriate logic and processing circuits, cause stimulation pulses tobe generated by the Output Stage 40 that are applied to at least one ofthe electrodes 32, in accordance with a programmed or selectedstimulation regime. The operating parameters associated with suchstimulation regime include, e.g., stimulation pulse amplitude, width,and frequency. Additionally, stimulation parameters may be programmed orselected that define the duration of a stimulation session (e.g. 15, 30,45 or 60 minutes), the frequency of the stimulation sessions (e.g.,daily, weekly, bi-weekly, etc.).

The Power Source 38 within the IEAD 30 may comprise a primary battery, arechargeable battery, a supercapacitor, or combinations or equivalentsthereof. For example, one embodiment of the power source 38, asdiscussed below in connection with FIG. 26, may comprise a combinationof a rechargeable battery and a supercapacitor.

When describing the power source 38, the terms “recharge”, “replenish”,“refill”, “reenergize”, and similar terms (or variations thereof), maybe used interchangeably to mean to put energy into a depleted reservoirof energy. Thus, e.g., a rechargeable battery when it is run down isrecharged. A supercapacitor designed to hold a large volume ofelectrical charge has its store of electrical charge replenished. Apower source that comprises a combination of a rechargeable battery anda supercapacitor, or similar devices, is reenergized. In other words, asthe stored energy within an EA device is consumed, or depleted, thestore of energy within the EA device, in some embodiments, may bereplenished, or the energy reservoir within the EA device is refilled.In other embodiments, the EA device may simply and easily be replaced.

The antenna coil 42 within the IEAD 30, when used (i.e., when the IEAD30 is coupled to the External Controller 20), receives an ac powersignal (or carrier signal) from the External Controller 20 that may bemodulated with control data. The modulated power signal is received anddemodulated by the receiver/demodulator circuit 44. (Thereceiver/demodulator circuit 44 in combination with the antenna coil 42may collectively be referred to as a receiver, or “RCVR”.) Typically thereceiver/demodulator circuit 44 includes simple diode rectification andenvelope detection, as is known in the art. The control data, obtainedby demodulating the incoming modulated power signal, is sent to theStimulation Control circuit 46 where it is used to define the operatingparameters and generate the control signals needed to allow the OutputStage 40 to generate the desired stimulation pulses.

It should be noted that the use of coils 24 and 42 to couple theexternal controller 20 to the IEAD 30 through, e.g., inductive or RFcoupling, of a carrier signal is not the only way the externalcontroller and IEAS may be coupled together, when coupling is needed(e.g., during programming and/or recharging). Optical or magneticcoupling, for example, may also be employed.

The control data, when present, may be formatted in any suitable mannerknown in the art. Typically, the data is formatted in one or morecontrol words, where each control word includes a prescribed number ofbits of information, e.g., 4 bits, 8 bits, or 16 bits. Some of thesebits comprise start bits, other bits comprise error correction bits,other bits comprise data bits, and still other bits comprise stop bits.

Power contained within the modulated power signal is used to recharge orreplenish the Power Source 38 within the IEAD 30. A return electrode 39is connected to a ground (GRD), or reference, potential within the IEAD30. This reference potential may also be connected to the housing 31(which housing is sometimes referred to herein as the “case”) of theIEAD 30.

A reed switch 48 may be employed within the IEAD 30 in some embodimentsto provide a means for the patient, or other medical personnel, to use amagnet placed on the surface of the skin 12 of the patient above thearea where the IEAD 30 is implanted in order to signal the IEAS thatcertain functions are to be enabled or disabled. For example, applyingthe magnet twice within a 2 second window of time could be used as aswitch to manually turn the IEAD 30 ON or OFF.

The Stimulation Control Circuit 46 used within the IEAD 30 contains theappropriate data processing circuitry to enable the Control Circuit 46to generate the desired stimulation pulses. More particularly, theControl Circuit 46 generates the control signals needed that will, whenapplied to the Output Stage circuit 40, direct the Output Stage circuit40 to generate the low intensity, low frequency and low duty cyclestimulation pulses used by the IEAD 30 as it follows the selectedstimulation regime. In one embodiment, the Control circuit 46 maycomprise a simple state machine realized using logic gates formed in anASIC. In other embodiments, it may comprise a more sophisticatedprocessing circuit realized, e.g., using a microprocessor circuit chip.

In the External Controller 20, the Power Source 22 provides operatingpower for operation of the External Controller 20. This operating poweralso includes the power that is transferred to the power source 38 ofthe IEAD 30 whenever the implanted power source 38 needs to bereplenished or recharged. Because the External Controller 20 is anexternal device, the power source 22 may simply comprise a replaceablebattery. Alternatively, it can comprise a rechargeable battery.

The External Controller 20 generates a power (or carrier) signal that iscoupled to the IEAD 30 when needed. This power signal is typically an RFpower signal (an AC signal having a high frequency, such as 40-80 MHz).An oscillator 27 is provided within the External Controller 20 toprovide a basic clock signal for operation of the circuits within theExternal Controller 20, as well as to provide, either directly or afterdividing down the frequency, the AC signal for the power or carriersignal.

The power signal is modulated by data in the modulator circuit 28. Anysuitable modulation scheme may be used, e.g., amplitude modulation,frequency modulation, or other modulation schemes known in the art. Themodulated power signal is then applied to the transmitting antenna orcoil 24. The external coil 24 couples the power-modulated signal to theimplanted coil 42, where the power portion of the signal is used toreplenish or recharge the implanted power source 38 and the data portionof the signal is used by the Stimulation Control circuit 46 to definethe control parameters that define the stimulation regime.

The memory circuit 25 within the External Controller 20 stores neededparameter data and other program data associated with the availablestimulation regimes that may be selected by the user. In someembodiments, only a limited number of stimulation regimes are madeavailable for the patient to use. Other embodiments may allow the useror other medical personnel to define one or more stimulation regimesthat is/are tailored to a specific patient.

Turning next to FIG. 24, there is shown a functional diagram of anOutput Stage 40-1 that may be used within the IEAD 30 for Embodiment III(See FIG. 18A and accompanying text for a description of EmbodimentIII). The Output Stage 40-1 is basically a pass-through circuit, whereinthe entire IEAD 30 comprises nothing more than an electrode 32 connectedto a coil 42-1, all of which is carried within an IEAD housing 31. Insome embodiments, some simple passive filtering circuitry 424 may alsobe used to filter and shape the signal being passed from the coil 42-1to the electrode(s) 32. Such a simple IEAD housing 31 allows themechanical functions of the IEAD 30 (size, implant location,effectiveness of EA stimulation, etc.) to be implanted and fully testedwithout initially incurring the additional expenses associated with afully functional IEAD 30.

As indicated in the previous paragraph, the function of the simplifiedIEAD 30 shown in FIG. 24 is to pass the signal received at the antennacoil 42-1 on to the electrode(s) 32. More particularly, a signal burst240, when applied to a coil 24-1 in the External Controller 20, iselectromagnetically (e.g., inductively) coupled to the coil 42-1 withinthe Output Stage 40-1 of the IEAD 30, where it appears as signal burst420. The signal burst 420 received by the implanted coil 42-1 may have adifferent intensity than does the signal burst 240 as a function of thecoupling efficiency between the two coils 24-1 and 42-1, the number ofturns in each coil, and the impedance matching that occurs between thecircuits of the External Controller 20 and the combined load attached tothe Output Circuit 40-1, which combined load includes the implanted coil42-1, the electrode 32 and the body tissue in contact with the electrode32. This different intensity may still be sufficiently controlled by theExternal Controller so that the energy contained within the signal burst420, defined in large part by the envelope of the signal burst 240, issufficient to stimulate the tissue at the desired electroacupuncturesite, or acupoint, thereby producing, over time, the desired therapeuticeffect.

In some embodiments, passive filtering circuitry 424 may also be usedwithin the Output Stage 401 to reconfigure or reshape the energy of thesignal burst 240 into a suitable stimulation pulse 422. This stimulationpulse 422 is then applied to the electrode 32 through a couplingcapacitor C.

As mentioned previously, the Output Stage circuit 40-1 shown in FIG. 24is ideally suited for diagnostic and data gathering purposes.Nonetheless, such embodiment can also be effectively used by a patientwho does not object to wearing an External Controller 20 on his or herwrist or leg when the stimulation sessions associated with use of the EASystem 10 are employed.

FIG. 25A functionally shows a representative Output Stage 40-2 that maybe used when voltage stimulation is applied through the electrode(s) 32to the desired acupoint. As seen in FIG. 25A, a positive voltage source,+V, and a negative voltage source, −V, are selectively and sequentiallyapplied to an electrode 32, through switches SW1 and SW2. A couplingcapacitor is preferably employed to prevent dc current from flowingthrough the electrode 32. If more than one electrode 32 is employed, asingle pair of voltage sources may be selectively connected to eachelectrode using a suitable multiplexer circuit (not shown in FIG. 6A),as is known in the art.

FIG. 25B functionally shows a representative Output Stage circuit 40-3that may be used when current stimulation is applied through theelectrode(s) 32 to the desired acupoint. As seen in FIG. 25B, a positivecurrent source, +I, and a negative current source, −I, are selectivelyapplied to an electrode 32. In some embodiments, the current sourcescomprise independent programmable current sources that can readily beprogrammed to source, or sink, a precise current magnitude, as is knownin the art. Advantageously, use of independent programmable currentsources in this fashion allows, when multiple electrodes 32 are used,precise sharing of the currents in order to steer the electric fieldsemanating from the electrodes in a desired manner. For example, if threeelectrodes 32 were employed, a first of which sources 200 microamps (μa)of current, and thus functions as an anode, and a second and third ofwhich each sink 100 μa, each thus functioning as cathodes, the resultingelectric fields would make it appear that a virtual electrode existed atsome point along a mid-point line between the second and thirdelectrodes. Such steering of a virtual electrode would thus allow theeffectiveness of the EA stimulation to be adjusted or tuned, whicheffectiveness is largely a function of the proximity between theacupoint site and the electrode, as well the spacing between thecathodes. (The cathodes must be sufficiently close together—less thanthe distance to the tissue target—for this type of adjustment or tuningto work.) Advantageously, this adjustment, or tuning, can occur evenafter the IEAD 30 is implanted with a fixed physical location of theelectrodes relative to the desired acupoint site.

FIG. 26 illustrates a power source configuration 38-1 that may be usedin some embodiments within the IEAD 30 for the implanted power source38. The power source configuration 38-1 shown in FIG. 26 employs both arechargeable battery 380 and a supercapacitor 382, connected inparallel. The rechargeable battery 380 is charged in conventional mannerusing power received from the recharge circuits. For most embodiments,this would be the power received through implanted coil 42 and theReceiver circuit 44 (see FIG. 23). The power stored in the battery 380may thereafter be used to trickle charge the supercapacitor at timeswhen the IEAD 30 is not stimulating body tissue. Then, when there is ademand for a pulse of stimulation current, the energy required for suchpulse may be pulled from the super capacitor in a relatively rapiddischarge mode of operation. Diodes D1 and D2 are used to isolate thesupercapitor 382 from the battery 380 when the supercapacitor isundergoing a rapid discharge.

Next, with respect to FIGS. 27 and 28, timing diagrams are shown toillustrate a typical stimulation regime that may be employed by the EASystem 10. First, as seen in FIG. 27, the electroacupuncture (EA)stimulation pulses preferably comprise a series of biphasic stimulationpulses of equal and opposite polarity for a defined time period T1seconds. Thus, as seen at the left edge of FIG. 27, a biphasicstimulation pulse 250 comprises a pulse having a positive phase ofamplitude +P1 followed by a negative phase having an amplitude of −P1.(Alternatively, the biphasic stimulation pulse could comprise a pulsehaving a negative phase of amplitude −P1 followed by a positive phase ofamplitude +P1.) Each phase has a duration of T1/2 seconds, or the entirebiphasic pulse has a total duration of T1/2+T1/2=T1 seconds. (Thisassumes the positive phase duration is equal to the negative phaseduration, which is usually the case for a biphasic stimulation pulse.)The rate at which the biphasic pulses occur is defined by the timeperiod T2 seconds. FIG. 27 makes it appear that T2 is approximatelytwice as long as T1. However, this is not necessarily the case. In manystimulation regimes, T2 may be many times longer than T1. For example,the time T1 may be only 20 milliseconds (ms), with each phase being 10ms, but the time T2 may be one second, or 1000 ms, or two seconds (2000ms). The time periods T1 (pulse width) and T2 (pulse rate) are thusimportant parameters that define a preferred stimulation regime. Theratio of T1/T2 defines the duty cycle of the stimulation pulses when thestimulation pulses are being applied during a stimulation session.

Still referring to FIG. 27, the next parameter shown is the stimulationsession period, or T3. This is the time over which stimulation pulses ofwidth T1 are applied at a rate T2. The session length T3, for example,may be 15, 30, 45, 60, or 70 minutes, or any other suitable value asselected by medical personnel for delivery to a specific patient.

The stimulation session, in turn, is also applied at a set rate, asdetermined by the time period T4. Typical times for T4 include 24 or 48hours, or longer, such as one week or two weeks. Thus, for example, ifT4 is 24 hrs. T3 is 30 minutes, T2 is 1 second, and T1 is 20 ms, thenbiphasic stimulation pulses having a width of 20 ms are applied onceeach second for a session time of 30 minutes. The session, in turn, isapplied once every 24 hours, or once each day.

It should be noted that bi-phasic stimulation pulses as shown in FIG. 27are not the only type of stimulation pulses that may be used. In SectionII, below, another type of stimulation pulse (a negative-going pulse) isused with the specific example described there. A negative-going pulseis shown in FIG. 15A.

Next, as seen in FIG. 28, several variations of possible stimulationpatterns are illustrated. In the top line of FIG. 28, a fixed ratestimulation sequence is illustrated where a stimulation session, havinga duration of T3 seconds, is applied at a rate defined by time periodT4. If T3 is 30 minutes, and T4 is 24 hours, then the fixed stimulationrate is one stimulation session lasting 30 minutes applied once eachday.

The second line of FIG. 28 shows a stimulation pattern that uses a fixedstimulation rate and a fixed replenishing rate, which rates are thesame, occurring every T4 seconds. A replenishing signal is a signal fromwhich energy is extracted for charging or replenishing the implantedpower source 38. Frequently, the replenishing signal may itself bemodulated with data, so that whenever replenishing occurs, control datamay also be transmitted. This control data can be new data, as when astimulation regime is to be followed, or it can just be the same data asused previously, and it is used just to refresh or re-store the existingcontrol data.

A replenishing signal is illustrated in FIG. 28 as pulses 260, which aredrawn having a higher amplitude than the stimulation session pulses, andwhich have a duration of T6 seconds. It is noted that the time scale inFIG. 28 is not drawn to scale. Thus, whereas as illustrated in FIG. 28the stimulation session time T3 appears to be twice as long as thereplenishment time T6, such is not necessarily the case.

The third line in FIG. 28 shows an example of a replenishment signalbeing generated every T5 hrs, and a stimulation session occurring everyT4 hours. As shown in FIG. 28, T4 is significantly less than T5. Forexample, T5 may be 168 hours (1 week), whereas T4 may be 24 hours, oronce a day.

The last line in FIG. 28 illustrates a manual selection of theoccurrence of a stimulation session and of a replenishment session.Hence, no rate is associated with either of these events. They simplyoccur whenever they are selected to occur. Selection can be made throughuse of the External Controller 20, or in the case of a stimulationsession (where no external recharging power is needed), through use ofthe reed switch 48). One type of manually-triggered stimulation isillustrated below in the flow diagram of FIG. 30.

Turning next to FIG. 29, a flow chart is shown that illustrates a method500 for automatically applying continuous stimulation sessions inaccordance with a prescribed stimulation regimen. Such method 500applies stimulation sessions having a fixed duration of T3 minutes everyT4 minutes. As seen in FIG. 29, such method is carried out by starting astimulation session (block 502). During the stimulation session, theelapsed time is monitored and a determination is made as to whether thetime period T3 has elapsed (block 504). If not (NO branch of block 504),the time monitoring continues. Once the time period T3 has elapsed (YESbranch of block 504), the stimulation session is stopped (block 506).However, even with the stimulation session stopped, time continues to bemonitored (block 508). When the time T4 has elapsed (YES branch of block508) then a determination is made as to whether a Shut Down mode shouldbe entered (block 510). If so (YES branch of block 510), then theapplication of stimulation sessions is stopped (block 512). If not (NObranch of block 510), then a new stimulation session of T3 minutesbegins (block 502), and the process continues. The timing waveformdiagram corresponding to the flow diagram of FIG. 29 is the top waveformin FIG. 28.

A variation of the method 500 depicted in FIG. 29 is to alternate thetime periods of the stimulation session duration, T3, between twodifferent values. That is, T3 is set to toggle between a first value T3₁for the stimulation session duration and a second value T3₂ for thestimulation session, with the value T3₁ being used every otherstimulation session. Thus, a time line of the method of treating amental illness follows a sequence T3₁-T4—T3₂-T4—T3₁-T4—T3₂-T4— . . . andso on, where T4 is the time period between stimulation sessions.

If such a method is followed of toggling between two values of T3,representative values for T3₁ and T3₂ could be to set T3₁ to a valuethat ranges between 10 minutes and 40 minutes, and to set T3₂ to a valuethat ranges between 30 minutes and 60 minutes.

Similarly, a further variation of this method of treating mental illnesswould be to toggle the value of T4, the time between stimulationsessions, between two values. That is, in accordance with this method,the time T4 would be set to toggle between a first value T4₁ and asecond value T4₂, with the value T4₁ being used after every otherstimulation session. Thus, a time line of this method of treating mentalillness would follow a sequence T3—T4₁-T3-T4₂-T3-T4₁-T3-T4₂-T3-T4₁ . . .and so on, where T3 is the duration of the stimulation sessions.

If such method is followed, representative values for T4₁ and T4₂ couldbe to set T4₁ to a value that ranges between 1440 minutes [1 day] and10,080 minutes [1 week], and to set T4₂ to a value that ranges between2,880 minutes [2 days] and 20,160 minutes [2 weeks].

Additional variations of these methods of toggling between differentvalues of T3 and T4 are also possible. For example, multiple values ofT3—T3₁, T3₂, T3₃, T3₄, T3₅ . . . T3_(n)—could be set, and then thevalues could be used in sequence, or randomly during successivestimulation sequences. Multiple values of T4 could also be employed, andthe various values of T3 and T4 could be combined together in thesequences followed.

Further, as has already been mentioned, the frequency of the stimuliapplied during a stimulation session can also vary. For example, duringa stimulation session the frequency may vary from 5 Hz to 15 Hz withseveral different frequencies applied during any session. If T3 is 45minutes, then the stimulation frequency of the stimulus pulses could be,e.g., 10 minutes at 12 Hz, then 10 minutes at 10 Hz, then 10 minutes at8 Hz, then 15 minutes at 6 Hz, for a total duration of 45 minutes. Theamplitude of the stimulus pulses at all frequencies could be constant orvaried, e.g., between 2 mA and 10 mA. The rate of occurrence forstimulus sessions, T4, could be set to be as infrequently as once everytwo weeks or as frequently as twice daily.

If such methods are used to adjust the values of T3 and T4, care must beexercised to not exceed the maximum duty cycle associated with thepreferred stimulation regimens. That is, the invention requires that theratio of T3/T4 be no greater than 0.05. Thus, if either, or both, T3 andT4 are varied, limits should be placed on the ranges the parameters canassume in order to preserve the desired duty cycle. For example, therange of values within which T3 may be selected is typically between 10minutes and 70 minutes. The ranges of values within which T4 may beselected is normally between about 24 hours and 2 weeks. However, as thevalue of T4 decreases, and the value of T3 increases, a point is reachedwhere the maximum duty cycle could be exceeded. Thus, to prevent themaximum duty cycle from exceeding 0.05, the range of values for T3 andT4 may be specified by setting the time T3, the duration of thestimulation sessions, to be at least 10 minutes but no longer than amaximum value, T3(max). The value of T3(max) is adjusted, as needed, tomaintain the duty cycle, the ratio of T3/T4, at a value no greater than0.05. Thus, T3(max) is equal to 72 minutes if T4, the time periodbetween stimulation sessions is between 1,440 minutes [24 hours] and20,160 minutes [14 days]. However, T3(max) should be set to a value setby the equation T3(max)=0.05*T4 when T4 is between 720 minutes [1/2 day]and 1,440 minutes [1 day].

Next, with reference to FIG. 30, there is depicted a flow chart for amethod 520 for manually triggering the application of stimulationsessions. When manual stimulation sessions are triggered, some basicparameters must still be observed. That is, there must be a minimumduration of a stimulation session T3(min), as well as a maximum durationof a stimulation session T3(max). Similarly, there needs to be a minimumtime period T4(min) that separates one stimulation session from another,and a maximum time period T4(max) allowed between stimulation sessionsbefore the next stimulation session is automatically started.Representative values for these parameters are, for example, T3(min)=10minutes, T3(max)=72 minutes, T4(min)=12 hours, and T4(max)=2 weeks.

With the basic operating parameters described above defined, the method520 shown in FIG. 29 proceeds by first determining whether a manualstart command (or trigger signal) has been received (block 522). If not(NO branch of block 522), then a determination is made as to whether thetime T4(max) has elapsed. If it has (YES branch of block 524), then astimulation session is started (block 526). If T4(max) has not elapsed(NO branch of block 524), then the IEAD 30 just keeps waiting for amanual trigger signal to occur (block 522).

If a manual trigger signal is received (YES branch of block 22), then adetermination is made as to whether T4(min) has elapsed (block 523).Only if T4(min) has elapsed (Yes branch of block 523) is a stimulationsession started (block 526). Thus, two consecutive stimulation sessionscannot occur unless at least the time T4(min) has elapsed since the laststimulation session.

During a stimulation session, the circuitry carrying out method 520 alsomonitors whether a manual stop signal has been received (block 528). Ifso (YES branch of block 528), then a determination is made as to whetherthe time T3(min) has elapsed. If not (NO branch of block 529), then thesession continues because the minimum session time has not elapsed. IfT3(min) has elapsed (YES branch of block 529), then the session isstopped (block 532). If a manual stop signal is not received (NO branchof block 528), and if T3(max) has not yet elapsed (NO branch of block530), then nothing happens (i.e., the session continues) until T3(max)has elapsed (YES branch of block 530), at which time the stimulationsession is terminated (block 532).

Still with reference to FIG. 30, once the session is stopped (block532), a determination is made whether the EA stimulation should shutdown (block 534). If so (YES branch of block 534) the stimulationterminates (block 536). If not, then the circuitry goes into a waitingmode where it monitors whether a manual start command is received, orthe time T4(max) elapses, whichever occurs first (blocks 522, 524), andthe next stimulation session is started (block 526). And, the processcontinues.

Thus, it is seen that the method 520 shown in FIG. 30 allows astimulation session to be manually started at any time a manual startcommand is received, providing that at least the time T4(min) haselapsed since the last session. Similarly, the method allows astimulation session to be manually stopped at any time during thestimulation session, providing that at least the time T3(min) haselapsed since the session started. Absent the occurrence of receiving amanual start command, the next session starts automatically afterT4(max) elapses. Similarly, during a stimulation session, absent a stopcommand, the session will stop automatically after the time T3(max) haselapsed.

Next, with reference to FIG. 31, a flow chart is shown that depicts onemethod 600 of using an EA System 10 of the type described herein, orequivalents thereof, to treat mental illness. It is emphasized that themethod shown in FIG. 31 is just one of many methods that may be used,and includes steps or actions taken that may not always be needed nordesired. (Note that each step in the flow chart shown in FIG. 31 isrepresented by a rectangular (or other shaped) block having a referencenumber assigned to it. Once the action or other activity indicated in astep, or block, of the method is completed, then the method flows to thenext step, or block, in the flow chart. Decision steps are representedby a diamond (4-sided) or hexagonal (6-sided) shape, also having areference number assigned to it.) For example, the method shown in FIG.31 includes three decision steps or blocks, 612, 616 and 620, where,depending on the question being asked, one of two paths or branches mustbe followed. In a simplified version or embodiment of the method,however, these three decision blocks may be eliminated. In suchsimplified method, the method reduces to following the steps shown inblocks 602, 604, 606, 608, 610, 614, 620 and 622, which blocks aredescribed below.

For the method that uses the three decision blocks, as seen in FIG. 31,the method outlined in the flow diagram of FIG. 31 assumes that thecondition, illness or other physiological deficiency (hereafter“Condition”) being treated by the EA system 10 has been identified.Then, the method begins at block 602, which requires identifying thelocation of the appropriate acupoint(s) for treating the Conditionthrough the application of appropriate EA Modulation. Recall that, asused herein, “EA modulation” is the application of electricalstimulation pulses, at low intensities, frequencies and duty cycles, toat least one of the acupuncture points that has been identified asaffecting a particular illness, deficiency or condition. For treatingmental illnes, the acupoints include GV20 and EXHN3. Other possibleacupoints also exist, as described previously. So, for purposes ofcompleting the step described at block 602, one of the possibleacupoints that could be used is selected as the target acupoint.

Once the location of the target acupoint to be modulated has beenidentified, the next step (block 604) is to implant the IEAS 30 so thatits electrodes are firmly anchored and located so as to be near or onthe target acupoint. Then, after waiting a sufficient time for healingto occur associated with the implant surgery (block 606), which isusually just a week or two, the next step is to program the IEAD 30 withthe parameters of the selected stimulation regime that is to be followedby the IEAD 30 as it applies EA modulation to the target acupoint (block608). The parameters that define the selected stimulation regime includethe time periods T1, T2, T3, T4, T5 and T6 (described in connection withthe description of FIGS. 27 and 28), the intensity P1 of the stimulationpulses (also described previously in connection with FIG. 27), and thenumber of weeks, k, that EA modulation is to be applied beforemonitoring the Condition to see if improvement has occurred, as well asthe number of weeks, j, that EA modulation should be turned off beforerestarting the same or a new EA Modulation regime.

Once implanted and programmed, EA Modulation begins and continues for aperiod of k weeks (block 610). After k weeks, the patient's Condition,in this case mental illness, is checked to see if it has improved(decision block 612). If YES, the EA Modulation is turned OFF for awaiting period of j weeks (block 614). After waiting j weeks, whilekeeping the EA Modulation deactivated, the Condition is again checked(decision block 616) to see if the condition has returned to itsprevious high blood pressure state, or to see if the improvement madehas lessened or deteriorated (decision block 616). If NOT, that is, ifthe Condition still remains at acceptable levels, then a decision may bemade by medical personnel in consultation with the patient as to whetherthe EA Modulation regime should be repeated in order to further help thepatient's body maintain the Condition at desired levels (decision block620).

If a decision is made to repeat the EA Modulation (YES branch ofdecision block 620), then the EA Modulation parameters are adjusted asneeded (block 622) and the EA Modulation begins again at the targetacupoint, following the programmed stimulation regime (block 610).

If a decision is made NOT to repeat the EA Modulation (NO branch ofdecision block 620), then that means the treatment for the Condition isover and the process stops (block 624). In such instance, the patientmay elect to have the IEAD 30 removed surgically, which is a very simpleprocedure.

Backtracking for a moment to decision block 612, where a decision wasmade as to whether the Condition had improved after the EA Modulationhad been applied for a period of k weeks, if the determination made isthat the Condition had not improved (NO branch of decision block 612),then again, medical personnel in consultation with the patient may makea decision as to whether the EA Modulation regime should be repeatedagain (block 620).

Further backtracking to decision block 616, where a decision was made asto whether, after the j weeks of applying no additional EA Modulation,the Condition had returned to its previous high blood pressure state, orthe improvement had lessened (YES branch of decision block 616), thenagain medical personnel in consultation with the patient may make adecision as to whether the EA Modulation regime should be repeated again(block 620).

In a simplified version of the method depicted in FIG. 31, only thesteps identified at blocks 602, 604, 606, 608, 610, 614, 620 and 622 arefollowed. This method thus reduces to identifying the target acupoint(block 602), implanting the IEAS at the target acupoint (block 604),waiting for the surgery to heal (block 606), programming EA simulationparameters into the IEAS (block 608) (which programming could actuallybe done before implanting the IEAS, if desired), applying EA modulationto the target acupoint for k weeks (block 610), turning off the EAmodulation for j weeks (block 614), adjusting or tweaking the EAstimulation parameters, if needed (block 622), and repeating the cycleover again starting with block 610.

II. Specific Example II. A. Overview

With the foregoing as a foundation for the general principles andconcepts of the present invention, a specific example of the inventionwill next be described in connection with a description of FIGS. 1-17B.Such specific example teaches one manner in which the general principlesand concepts described above may be applied to one specificelectroacupuncture (EA) device, or IEAD. Although one specific exampleis being described, there are many variations of it that are generallyreferred to in the description of the specific example as “embodiments”.Also, it should be noted that because the description of the specificexample is presented in conjunction with a different set of drawings,FIGS. 1-17B, than were used to describe the general principles andconcepts of the invention, FIGS. 18-31, there will be some differencesin the reference numerals used in connection with one set of drawingsrelative to the reference numerals used in connection with the other setof drawings to describe the same or similar elements. However, suchdifferent reference numerals should not be a source of confusion becausethe context of how and where the references numerals are presented willclearly identify what part or element is being referenced.

The EA device of this specific example is an implantable, coin-shaped,self-contained, symmetrical, leadless electroacupuncture (EA) devicehaving at least two electrode contacts mounted on the surface of itshousing. In one preferred embodiment, the electrodes include a centralcathode electrode on a front side of the housing, and an annular anodeelectrode that surrounds the cathode. In another preferred embodiment,the anode annular electrode is a ring electrode placed around theperimeter edge of the coin-shaped housing.

The EA device is leadless. This means there are no leads or electrodesat the distal end of leads (common with most implantable electricalstimulators) that have to be positioned and anchored at a desiredstimulation site. Also, because there are no leads, no tunneling throughbody tissue is required in order to provide a path for the leads toreturn and be connected to a tissue stimulator (also common with mostelectrical stimulators).

The EA device is adapted to be implanted through a small incision, e.g.,less than 2-3 cm in length, directly adjacent to a selected acupuncturesite (“acupoint”) known to moderate or affect a mental illness symptomof depression related to a patient's mental illness.

The EA device is relatively easy to implant. Also, most embodiments aresymmetrical. This means that there is no way that it can be implantedincorrectly. The basic implant procedure involves cutting an incision,forming an implant pocket, and sliding the device in place through theincision. Only minor, local anesthesia need be used. No major orsignificant complications are envisioned for the implant procedure. TheEA device can also be easily and quickly explanted, if needed.

The EA device is self-contained. It includes a primary battery toprovide its operating power. It includes all of the circuitry it needs,in addition to the battery, to allow it to perform its intended functionfor several years. Once implanted, the patient will not even know it isthere, except for a slight tingling that may be felt when the device isdelivering stimulus pulses during a stimulation session. Also, onceimplanted, the patient can just forget about it. There are nocomplicated user instructions that must be followed. Just turn it on. Nomaintenance is needed. Moreover, should the patient want to disable theEA device, i.e., turn it OFF, or change stimulus intensity, he or shecan easily do so using, e.g., an external magnet.

The EA device can operate for several years because it is designed to bevery efficient. Stimulation pulses applied by the EA device at aselected acupoint through its electrodes formed on its case are appliedat a very low duty cycle in accordance with a specified stimulationregimen. The stimulation regimen applies EA stimulation during astimulation session that lasts at least 10 minutes, typically 30minutes, and rarely longer than 70 minutes. These stimulation sessions,however, occur at a very low duty cycle. In one preferred treatmentregimen, for example, a stimulation session having a duration of 60minutes is applied to the patient just once every seven days. Thestimulation regimen, and the selected acupoint at which the stimulationis applied, are designed and selected to provide efficient and effectiveEA stimulation for the treatment of the patient's mental illness (e.g.,depression, Anxiety, or bipolar disorder).

The EA device is, compared to most implantable medical devices,relatively easy to manufacture and uses few components. This not onlyenhances the reliability of the device, but helps keep the manufacturingcosts low, which in turn allows the device to be more affordable to thepatient. One key feature included in the mechanical design of the EAdevice is the use of a radial feed-through assembly to connect theelectrical circuitry inside of its housing to one of the electrodes onthe outside of the housing. The design of this radial feed-through pinassembly greatly simplifies the manufacturing process. The processplaces the temperature sensitive hermetic bonds used in the assembly—thebond between a pin and an insulator and the bond between the insulatorand the case wall—away from the perimeter of the housing as the housingis hermetically sealed at the perimeter with a high temperature laserwelding process, thus preserving the integrity of the hermetic bondsthat are part of the feed-through assembly.

In operation, the EA device is safe to use. There are no horrificfailure modes that could occur. Because it operates at a very low dutycycle (i.e., it is OFF much, much more than it is ON), it generateslittle heat. Even when ON, the amount of heat it generates is not much,less than 1 mW, and is readily dissipated. Should a component or circuitinside of the EA device fail, the device will simply stop working. Ifneeded, the EA device can then be easily explanted.

Another key feature included in the design of the EA device is the useof a commercially-available battery as its primary power source. Small,thin, disc-shaped batteries, also known as “coin cells,” are quitecommon and readily available for use with most modern electronicdevices. Such batteries come in many sizes, and use variousconfigurations and materials. However, insofar as applicants are aware,such batteries have never been used in implantable medical devicespreviously. This is because their internal impedance is, or has alwaysthought to have been, much too high for such batteries to be ofpractical use within an implantable medical device where powerconsumption must be carefully monitored and managed so that the device'sbattery will last as long as possible, and so that dips in the batteryoutput voltage (caused by any sudden surge in instantaneous batterycurrent) do not occur that could compromise the performance of thedevice. Furthermore, the energy requirements of other active implantabletherapies are far greater than can be provided by such coin cellswithout frequent replacement.

The EA device of this specific example advantageously employspower-monitoring and power-managing circuits that prevent any suddensurges in battery instantaneous current, or the resulting drops inbattery output voltage, from ever occurring, thereby allowing a wholefamily of commercially-available, very thin, high-output-impedance,relatively low capacity, small disc batteries (or “coin cells”) to beused as the EA device's primary battery without compromising the EAdevice's performance. As a result, instead of specifying that the EAdevice's battery must have a high capacity, e.g., greater than 200 mAh,with an internal impedance of, e.g., less than 5 ohms, which wouldeither require a thicker battery and/or preclude the use ofcommercially-available coin-cell batteries, the EA device of the presentinvention can readily employ a battery having a relatively low capacity,e.g., less than 60 mAh, and a high battery impedance, e.g., greater than5 ohms.

Moreover, the power-monitoring, power-managing, as well as the pulsegeneration, and control circuits used within the EA device arerelatively simple in design, and may be readily fashioned fromcommercially-available integrated circuits (IC's) orapplication-specific integrated circuits (ASIC's), supplemented withdiscrete components, as needed. In other words, the electronic circuitsemployed within the EA device need not be complex nor expensive, but aresimple and inexpensive, thereby making it easier to manufacture the EAdevice and to provide it to patients at an affordable cost.

II. B. Illnesses Addressed, Stimulation Sites and Regimen

The EA device of this specific example is aimed at treating mentalillness, and more particularly three types of mental illness: (i)depression, (ii) Anxiety, and (iii) bipolar disorder. This it does byapplying EA stimulation pulses to two acupoints, EXHN3 and/or GV20, orthe nerves underlying these acupoints, in accordance with a specificstimulation regimen.

Duration of a stimulation session will typically be about 60 minutes,but could be as short as about 10 minutes and as long as about 70minutes. The time between stimulation sessions (or the rate ofoccurrence of the stimulation session) may be as short as twenty-fourhours and as long as two weeks. The duty cycle of the stimulationsessions, T3/T4, should never be allowed to be greater than 0.05, whereT3 is the duration of the stimulation session, and T4 is the time periodbetween the start of one stimulation session and the beginning of thenext stimulation session.

By way of example, if T3 is 60 minutes, and T4 is 2 weeks (10,080minutes), then the duty cycle is 60/10,080=0.006 (a very low stimulationsession duty cycle). If T3 is 60 minutes and T4 is 1 day (24 hours, or1440 minutes), then the duty cycle is 60/1440=0.042 (still, a very lowsession duty cycle, but approaching the duty cycle limit of 0.05).

The amplitude of stimulation is adjustable and is set to a comfortablelevel depending upon the particular patient. Ideally, the patient willfeel or sense the stimulation as a slight tingling sensation at theacupoint location where the EA stimulation is applied. If the tinglingsensation becomes uncomfortable, then the intensity (e.g., amplitude) ofthe EA stimulation pulses should be decreased until the sensation iscomfortable. Typically, the amplitude of the stimulation pulses may beset to be as low as 1-2 mA and as high as 10-12 mA.

The frequency of the EA stimulation pulses should be nominally 2 Hz, butcould be as low as 1 Hz and as high as 3 Hz. In one variation of thestimulation regimen, the frequency of the stimulation pulses is variedduring the stimulation session. For example, if the stimulation sessionhas a duration of 45 minutes, 10 minutes of that 45 minutes may comprisestimulation pulses at 12 Hz, then the next 10 minutes may comprisestimulation pulses at 10 Hz, then 10 minutes at 8 Hz, then 15 minutes at6 Hz for a total duration of 45 minutes.

The width of the EA stimulation pulses is about 0.5 millisecond, butcould be as short as 0.1 millisecond (100 microseconds), or as long as 2millisecond (2000 microseconds), or longer. The duty cycle of theapplied EA stimulation pulses, T1/T2, during a stimulation session islimited to no more than 0.05, where T1 is the width of a stimulationpulse and T2 is the time period between the beginning of one stimulationpulse and the beginning of the next stimulation pulse. By way ofexample, if T1 is 0.5 milliseconds, and T2 is 0.5 seconds (500milliseconds, providing a rate of 2 Hz), then the duty cycle of thestimulus pulses during a stimulation session is 0.5/500=0.001 (a verylow stimulus duty cycle).

II. C. Definitions

As used herein, “annular”, “circumferential”, “circumscribing”,“surrounding” or similar terms used to describe an electrode orelectrode array, or electrodes or electrode arrays, (where the phrase“electrode or electrode array,” or “electrodes or electrode arrays,” isalso referred to herein as “electrode/array,” or “electrodes/arrays,”respectively) refers to an electrode/array shape or configuration thatsurrounds or encompasses a point or object, such as another electrode,without limiting the shape of the electrode/array or electrodes/arraysto be circular or round. In other words, an “annular” electrode/array(or a “circumferential” electrode/array, or a “circumscribing”electrode/array, or a “surrounding” electrode/array), as used herein,may be many shapes, such as oval, polygonal, starry, wavy, and the like,including round or circular.

“Nominal” or “about” when used with a mechanical dimension, e.g., anominal diameter of 23 mm, means that there is a tolerance associatedwith that dimension of no more than plus or minus (+/−) 5%. Thus, adimension that is nominally 23 mm means a dimension of 23 mm+/−(0.05×23mm=1.15 mm).

“Nominal” when used to specify a battery voltage is the voltage by whichthe battery is specified and sold. It is the voltage you expect to getfrom the battery under typical conditions, and it is based on thebattery cell's chemistry. Most fresh batteries will produce a voltageslightly more than their nominal voltage. For example, a new nominal 3volt lithium coin-sized battery will measure more than 3.0 volts, e.g.,up to 3.6 volts under the right conditions. Since temperature affectschemical reactions, a fresh warm battery will have a greater maximumvoltage than a cold one. For example, as used herein, a “nominal 3 volt”battery voltage is a voltage that may be as high as 3.6 volts when thebattery is brand new, but is typically between 2.7 volts and 3.4 volts,depending upon the load applied to the battery (i.e., how much currentis being drawn from the battery) when the measurement is made and howlong the battery has been in use.

II. D. Mechanical Design

Turing first to FIG. 1, there is shown a perspective view of onepreferred embodiment of an implantable electroacupuncture device (IEAD)100 that may be used to treat depression, Anxiety, bipolar disorder,PTSD, schizophrenia, or OCD in accordance with the teachings disclosedherein. The IEAD 100 may also sometimes be referred to as an implantableelectroacupuncture stimulator (IEAS). As seen in FIG. 1, the IEAD 100has the appearance of a disc or coin, having a front side 102, a backside 106 (not visible in FIG. 1) and an edge side 104.

As used herein, the “front” side of the IEAD 100 is the side that ispositioned so as to face the target stimulation point (e.g., the desiredacupoint) where EA is to be applied when the IEAD is implanted. The“back” side is the side opposite the front side and is the farthest awayfrom the target stimulation point when the IEAD is implanted. The “edge”of the IEAD is the side that connects or joins the front side to theback side. In FIG. 1, the IEAD 100 is oriented to show the front side102 and a portion of the edge side 104.

Many of the features associated with the mechanical design of the lEAD100 shown in FIG. 1 are the subject of a prior U.S. Provisional PatentApplication, entitled “Radial Feed-Through Packaging for An ImplantableElectroacupuncture Device”, Application No. 61/676,275, filed 26 Jul.2012, which application is incorporated here by reference.

It should be noted here that throughout this application, the terms lEAD100, IEAD housing 100, bottom case 124, can 124, or IEAD case 124, orsimilar terms, are used to describe the housing structure of the EAdevice. In some instances it may appear these terms are usedinterchangeably. However, the context should dictate what is meant bythese terms. As the drawings illustrate, particularly FIG. 7, there is abottom case 124 that comprises the “can” or “container” wherein thecomponents of the IEAD 100 are first placed and assembled duringmanufacture of the IEAD 100. When all of the components are assembledand placed within the bottom case 124, a cover plate 122 is welded tothe bottom case 124 to form the hermetically-sealed housing of the IEAD.The cathode electrode 110 is attached to the outside of the bottom case124 (which is the front side 102 of the device), and the ring anodeelectrode 120 is attached, along with its insulating layer 129, aroundthe perimeter edge 104 of the bottom case 124. Finally, a layer ofsilicone molding 125 covers the IEAD housing except for the outsidesurfaces of the anode ring electrode and the cathode electrode.

The embodiment of the IEAD 100 shown in FIG. 1 utilizes two electrodes,a cathode electrode 110 that is centrally positioned on the front side102 of the IEAD 100, and an anode electrode 120. The anode electrode 120is a ring electrode that fits around the perimeter edge 104 of the IEAD100. Not visible in FIG. 1, but which is described hereinafter inconnection with the description of FIG. 7, is a layer of insulatingmaterial 129 that electrically insulates the anode ring electrode 120from the perimeter edge 104 of the housing or case 124.

Not visible in FIG. 1, but a key feature of the mechanical design of theIEAD 100, is the manner in which an electrical connection is establishedbetween the ring electrode 120 and electronic circuitry carried insideof the IEAD 100. This electrical connection is established using aradial feed-through pin that fits within a recess formed in a segment ofthe edge of the case 124, as explained more fully below in connectionwith the description of FIGS. 5, 5A, 5B and 7.

In contrast to the feed-through pin that establishes electrical contactwith the anode electrode, electrical connection with the cathodeelectrode 110 is established simply by forming or attaching the cathodeelectrode 110 to the front surface 102 of the IEAD case 124. In order toprevent the entire case 124 from functioning as the cathode (which isdone to better control the electric fields established between the anodeand cathode electrodes), the entire IEAD housing is covered in a layerof silicone molding 125 (see FIG. 7), except for the outside surface ofthe anode ring electrode 120 and the cathode electrode 110.

The advantage of using a central cathode electrode and a ring anodeelectrode is described in U.S. Provisional Patent Application No.61/672,257, filed 6 Mar. 2012, entitled “Electrode Configuration forImplantable Electroacupuncture Device”, which application isincorporated herein by reference. One significant advantage of thiselectrode configuration is that it is symmetrical. That is, whenimplanted, the surgeon or other medical personnel performing the implantprocedure, need only assure that the cathode side of the IEAD 100, which(for the embodiment shown in FIGS. 1-7) is the front side of the device,facing the target tissue location that is to be stimulated.

In this regard, it should be noted that while the target stimulationpoint is generally identified by an “acupoint,” which is typically shownin drawings and diagrams as residing on the surface of the skin, thesurface of the skin is not the actual target stimulation point. Rather,whether such stimulation comprises manual manipulation of a needleinserted through the skin at the location on the skin surface identifiedas an “acupoint”, or whether such stimulation comprises electricalstimulation applied through an electrical field oriented to causestimulation current to flow through the tissue at a prescribed depthbelow the acupoint location on the skin surface, the actual targettissue point to be stimulated is located beneath the skin at a depththat varies depending on the particular acupoint location. Whenstimulation is applied at the target tissue point, such stimulation iseffective at treating a selected condition of the patient, e.g.,depression, because there is something in the tissue at that location,or near that location, such as a nerve, a tendon, a muscle, or othertype of tissue, that responds to the applied stimulation in a mannerthat contributes favorably to the treatment of the condition experiencedby the patient.

For purposes of the present application, where the desired acupoints arelocated on the head of the patient, e.g., acupoints GV20 and/or EXHN3,see FIGS. 1A and 1B, the location of the patient's skull prevents deeptissue stimulation. This is illustrated schematically in FIGS. 17A and17B. As seen in these figures, the skull 89 is generally right under theskin 80, with not much tissue separating the two. These two figuresassume that the actual desired target stimulation point is a nerve 87(or some other tissue formation) between the underneath side of the skin80 and the top surface of the skull 89. Hence, the challenge is toimplant the IEAD 100 in a manner that provides effective EA stimulationat the desired target stimulation site, e.g., at the nerve 87 (or othertissue formation) that resides beneath the acupoint 90. FIGS. 17A and17B illustrate alternative methods for achieving this goal.

Shown in FIG. 17A is one alternative for implanting the IEAD 100 at anacupoint 90 located on the surface of the skin 80 above the skull 89,where the actual target stimulation point is a nerve 87, or some othertissue formation, that is located between the skull 89 and theunderneath side of the skin 80. As shown in FIG. 17A, the IEAD 100 isimplanted right under the skin with its front surface 102 facing downtowards the target tissue location 87. This allows the electric fields(illustrated by the electric field gradient lines 88) generated by theIEAD 100 when EA stimulation pulses are to be generated to be mostheavily concentrated at the target tissue stimulation site 87. Theseelectric field gradient lines 88 are established between the twoelectrodes 110 and 120 of the IEAD. For the embodiment shown here, thesetwo electrodes comprise a ring electrode 120, positioned around theperimeter edge of the IEAD housing, and a central electrode 110,positioned in the center of the front surface 102 of the IEAD housing.These gradient lines 88 are most concentrated right below the centralelectrode, which is where the target tissue location 87 resides. Hence,the magnitude of the electrical stimulation current will also be mostconcentrated at the target tissue location 87, which is the desiredresult.

FIG. 17B shows another alternative for implanting the IEAD 100 at theacupoint 90 located on the surface of the skin 80 above the skull 89,where the actual target stimulation point is a nerve 87, or some othertissue formation, that is located between the skull 89 and theunderneath side of the skin 80. As shown in FIG. 17B, the IEAD 100 isimplanted in a pocket 81 formed in the skull 89 at a location underneaththe acupoint 90. In this instance, and as the elements are oriented inFIG. 17B, the front surface 102 of the IEAD 100 faces upwards towardsthe target tissue location 87. As with the implant configuration shownin FIG. 17A, this configuration also allows the electric fields(illustrated by the electric field gradient lines 88) that are generatedby the IEAD 100 when EA stimulation pulses are generated to be mostheavily concentrated at the target tissue stimulation site 87.

There are advantages and disadvantages associated with each of the twoalternative implantation configurations shown in FIGS. 17A and 17B.Generally, the implantation procedure used to achieve the configurationshown in FIG. 17A is a simpler procedure with less risks. That is, allthat need to be done by the surgeon to implant that EA device 100 asshown in FIG. 17A is to make an incision 82 in the skin 80 a shortdistance, e.g., 10-15 mm, away from the acupoint 90. This incisionshould be made away from the nerve 87 so as to minimize the risk ofcutting the nerve 87. A slot is then formed at the incision by liftingthe skin closest to the acupoint up at the incision and by carefullysliding the IEAD 100, with its front side 102 facing the skull, into theslot so that the center of the IEAD is located under the acupoint 90.Care is taken to assure that the nerve 87 resides below the frontsurface of the IEAD 100 as the IEAD is slid into position.

In contrast, if the implant configuration shown in FIG. 17B is to beused, then the implant procedure is somewhat more complicated withsomewhat more risks. That is, to achieve the implant configuration shownin FIG. 17B, a sufficiently large incision must be made in the skin atthe acupoint 90 to enable the skin 80 to be peeled or lifted away toexpose the surface of the skull so that the cavity 81 may be formed inthe skull bone. While doing this, care must be exercised to hold thenerve 87 (or other sensitive tissue areas) away from the cutting toolsused to form the cavity 81. Once the cavity 81 is formed, the IEAD 100is laid in the cavity, with its front surface facing upward, the nerve87 (and other sensitive tissue areas) are carefully repositioned abovethe IEAD 100, and the skin is sewn or clamped to allow the incision toheal.

However, while the surgical procedure and attendant risks may be morecomplicated when the configuration of FIG. 17B is employed, the finalresults of the configuration of FIG. 17B may be more aestheticallypleasing to the patient than are achieved with the configuration of FIG.17A. That is, given the shallow space between the skin and the skull atacupoints GV20 and EXHN3, the implant configuration of FIG. 17A willlikely result in a small hump or bump at the implant site.

Insofar as Applicant is aware at the present time, of the two implantconfigurations shown in FIGS. 17A and 17B, there is no theoreticalperformance advantage that one implant configuration provides over theother. That is, both implant configurations should perform equally wellinsofar as providing EA stimulation pulses at the desired target tissuelocation 87 is concerned.

Thus, which implant configuration is used will, in large part, bedictated by individual differences in patient anatomy, patientpreference, and surgeon preferences and skill levels.

(As an aside, it should be pointed out that if a different type ofhousing is employed for the EA device, other than the coin-shapedhousing used for purposes of this specific example, then many of theissues discussed above are mitigated. For example, if a pigtail lead isemployed, or if a device housing with a shovel nose is used, then thetarget tissue can be activated above and below the electrode since theEA device is away from the electrode and target tissue. Some alternatedevice housing shapes are disclosed in FIGS. 20-22E, as well as inAppendix E.)

From the above, it is seen that one of the main advantages of using asymmetrical electrode configuration that includes a centrally locatedelectrode surrounded by an annular electrode, as is used in theembodiment described in connection with FIGS. 1-7, is that the preciseorientation of the IEAD 100 within its implant location is notimportant. So long as one electrode faces and is centered over thedesired target location, and the other electrode surrounds the firstelectrode (e.g., as an annular electrode), a strong electric fieldgradient is created that is aligned with the desired target tissuelocation. This causes the EA stimulation current to flow at (or verynear to) the target tissue location 87.

FIG. 2 shows a plan view of the “front” side of the IEAD 100. As seen inFIG. 2, the cathode electrode 110 appears as a circular electrode,centered on the front side, having a diameter D1. The IEAD housing has adiameter D2 and an overall thickness or width W2. For the preferredembodiment shown in these figures, D1 is about 4 mm, D2 is about 23 mmand W2 is a little over 2 mm (2.2 mm).

FIG. 2A shows a side view of the IEAD 100. The ring anode electrode 120,best seen in FIG. 2A, has a width W1 of about 1.0 mm, or approximately ½of the width W2 of the IEAD.

FIG. 3 shows a plan view of the “back” side of the IEAD 100. As will beevident from subsequent figure descriptions, e.g., FIGS. 5A and 5B, theback side of the IEAD 100 comprises a cover plate 122 that is welded inplace once the bottom case 124 has all of the electronic circuitry, andother components, placed inside of the housing.

FIG. 3A is a sectional view of the IEAD 100 of FIG. 1 taken along theline A-A of FIG. 3. Visible in this sectional view is the feed-throughpin 130, including the distal end of the feed-through pin 130 attachedto the ring anode electrode 120. Also visible in this section view is anelectronic assembly 133 on which various electronic components aremounted, including a disc-shaped battery 132. FIG. 3A furtherillustrates how the cover plate 122 is welded, or otherwise bonded, tothe bottom case 124 in order to form the hermetically-sealed IEADhousing 100.

FIG. 4 shows a perspective view of the IEAD case 124, including thefeed-through pin 130, before the electronic components are placedtherein, and before being sealed with the “skin side” cover plate 122.The case 124 is similar to a shallow “can” without a lid, having a shortside wall around its perimeter. Alternatively, the case 124 may beviewed as a short cylinder, closed at one end but open at the other.(Note, in the medical device industry the housing of an implanted deviceis often referred to as a “can”.) The feed-through pin 130 passesthrough a segment of the wall of the case 124 that is at the bottom of arecess 140 formed in the wall. The use of this recess 140 to hold thefeed-through pin 130 is a key feature of the invention because it keepsthe temperature-sensitive portions of the feed-through assembly (thoseportions that could be damaged by excessive heat) away from the thermalshock and residual weld stress inflicted upon the case 124 when thecover plate 122 is welded thereto.

FIG. 4A is a side view of the IEAD case 124, and shows an annular rim126 formed on both sides of the case 124. The ring anode electrode 120fits between these rims 126 once the ring electrode 120 is positionedaround the edge of the case 124. (This ring electrode 120 is, for mostconfigurations, used as an anode electrode. Hence, the ring electrode120 may sometimes be referred to herein as a ring anode electrode.However, it is noted that the ring electrode could also be employed as acathode electrode, if desired.) A silicone insulator layer 129 (see FIG.7) is placed between the backside of the ring anode electrode 120 andthe perimeter edge of the case 124 where the ring anode electrode 120 isplaced around the edge of the case 124.

FIG. 5 shows a plan view of the empty IEAD case 124 shown in theperspective view of FIG. 4. An outline of the recess cavity 140 is alsoseen in FIG. 5, as is the feed-through pin 130. A bottom edge of therecess cavity 140 is located a distance D5 radially inward from the edgeof the case 124. In one embodiment, the distance D5 is between about 2.0to 2.5 mm. The feed-through pin 130, which is just a piece of solidwire, is shown in FIG. 5 extending radially outward from the case 124above the recess cavity 140 and radially inward from the recess cavitytowards the center of the case 124. The length of this feed-through pin130 is trimmed, as needed, when a distal end (extending above therecess) is connected (welded) to the anode ring electrode 120 (passingthrough a hole in the ring electrode 120 prior to welding) and when aproximal end of the feed-through pin 130 is connected to an outputterminal of the electronic assembly 133.

FIG. 5A depicts a sectional view of the IEAD housing 124 of FIG. 5 takenalong the section line A-A of FIG. 5. FIG. 5B shows an enlarged view ordetail of the portion of FIG. 5A that is encircled with the line B.Referring to FIGS. 5A and 5B jointly, it is seen that the feed-throughpin 130 is embedded within an insulator material 136, which insulatingmaterial 136 has a diameter of D3. The feed-through pin assembly (whichpin assembly comprises the combination of the pin 130 embedded into theinsulator material 136) resides on a shoulder around an opening or holeformed in the bottom of the recess 140 having a diameter D4. For theembodiment shown in FIGS. 5A and 5B, the diameter D3 is 0.95-0.07 mm,where the −0.07 mm is a tolerance. (Thus, with the tolerance considered,the diameter D3 may range from 0.88 mm to 0.95 mm) The diameter D4 is0.80 mm with a tolerance of −0.06 mm. (Thus, with the toleranceconsidered, the diameter D4 could range from 0.74 mm to 0.80 mm).

The feed-through pin 130 is preferably made of pure platinum 99.95%. Apreferred material for the insulator material 136 is Ruby or alumina.The IEAD case 124, and the cover 122, are preferably made from titanium.The feed-through assembly, including the feed-through pin 130,ruby/alumina insulator 136 and the case 124 are hermetically sealed as aunit by gold brazing. Alternatively, active metal brazing can be used.(Active metal brazing is a form of brazing which allows metal to bejoined to ceramic without metallization.)

The hermeticity of the sealed IEAD housing is tested using a helium leaktest, as is common in the medical device industry. The helium leak rateshould not exceed 1×10⁻⁹ STD cc/sec at 1 atm pressure. Other tests areperformed to verify the case-to-pin resistance (which should be at least15×10⁶ Ohms at 100 volts DC), the avoidance of dielectric breakdown orflashover between the pin and the case 124 at 400 volts AC RMS at 60 Hzand thermal shock.

One important advantage provided by the feed-through assembly shown inFIGS. 4A, 5, 5A and 5B is that the feed-through assembly made from thefeed-through pin 130, the ruby insulator 136 and the recess cavity 140(formed in the case material 124) may be fabricated and assembled beforeany other components of the IEAD 100 are placed inside of the IEAD case124. This advantage greatly facilitates the manufacture of the IEADdevice.

Turning next to FIG. 6, there is shown a perspective view of anelectronic assembly 133. The electronic assembly 133 includes amulti-layer printed circuit (pc) board 138, or equivalent mountingstructure, on which a battery 132 and various electronic components 134are mounted. This assembly is adapted to fit inside of the empty bottomhousing 124 of FIG. 4 and FIG. 5.

FIGS. 6A and 6B show a plan view and side view, respectively, of theelectronic assembly 133 shown in FIG. 6. The electronic components areassembled and connected together so as to perform the circuit functionsneeded for the IEAD 100 to perform its intended functions. These circuitfunctions are explained in more detail below under the sub-heading“Electrical Design”. Additional details associated with these functionsmay also be found in many of the co-pending patent applicationsreferenced above in Paragraph [0001].

FIG. 7 shows an exploded view of the complete IEAD 100, illustrating itsmain constituent parts. As seen in FIG. 7, the IEAD 100 includes,starting on the right and going left, a cathode electrode 110, a ringanode electrode 120, an insulating layer 129, the bottom case 124 (the“can” portion of the IEAD housing, and which includes the feed-throughpin 130 which passes through an opening in the bottom of the recess 140formed as part of the case, but wherein the feed-through pin 130 isinsulated and does not make electrical contact with the metal case 124by the ruby insulator 136), the electronic assembly 133 (which includesthe battery 132 and various electronic components 134 mounted on a pcboard 138) and the cover plate 122. The cover plate 122 is welded to theedge of the bottom case 124 using laser beam welding, or some equivalentprocess, as one of the final steps in the assembly process.

Other components included in the IEAD assembly, but not necessarilyshown or identified in FIG. 7, include adhesive patches for bonding thebattery 132 to the pc board 138 of the electronic assembly 133, and forbonding the electronic assembly 133 to the inside of the bottom of thecase 124. To prevent high temperature exposure of the battery 132 duringthe assembly process, conductive epoxy is used to connect a batteryterminal to the pc board 138. Because the curing temperature ofconductive epoxy is 125° C., the following process is used: (a) firstcure the conductive epoxy of a battery terminal ribbon to the pc boardwithout the battery, (b) then glue the battery to the pc board usingroom temperature cure silicone, and (c) laser tack weld the connectingribbon to the battery.

Also not shown in FIG. 7 is the manner of connecting the proximal end ofthe feed-through pin 130 to the pc board 138, and connecting a pc boardground pad to the case 124. A preferred method of making theseconnections is to use conductive epoxy and conductive ribbons, althoughother connection methods known in the art may also be used.

Further shown in FIG. 7 is a layer of silicon molding 125 that is usedto cover all surfaces of the entire IEAD 100 except for the anode ringelectrode 120 and the circular cathode electrode 110. An overmodlingprocess is used to accomplish this, although overmolding using siliconeLSR 70 (curing temperature of 120° C.) with an injection moldlingprocess cannot be used. Overmolding processes that may be used include:(a) molding a silicone jacket and gluing the jacket onto the case usingroom temperature cure silicone (RTV) inside of a mold, and curing atroom temperature; (b) injecting room temperature cure silicone in a PEEKor Teflon® mold (silicone will not stick to the Teflon® or PEEKmaterial); or (c) dip coating the IEAD 100 in room temperature curesilicone while masking the electrode surfaces that are not to be coated.(Note: PEEK is a well known semicrystalline thermoplastic with excellentmechanical and chemical resistance properties that are retained at hightemperatures.)

When assembled, the insulating layer 129 is positioned underneath thering anode electrode 120 so that the anode electrode does not short tothe case 124. The only electrical connection made to the anode electrode120 is through the distal tip of the feed-through pin 130. Theelectrical contact with the cathode electrode 110 is made through thecase 124. However, because the entire IEAD is coated with a layer ofsilicone molding 125, except for the anode ring electrode 120 and thecircular cathode electrode 110, all stimulation current generated by theIEAD 100 must flow between the exposed surfaces of the anode andcathode.

It is noted that while the preferred configuration described herein usesa ring anode electrode 120 placed around the edges of the IEAD housing,and a circular cathode electrode 110 placed in the center of the cathodeside of the IEAD case 124, such an arrangement could be reversed, i.e.,the ring electrode could be the cathode, and the circular electrodecould be the anode.

Moreover, the location and shape of the electrodes may be configureddifferently than is shown in the one preferred embodiment describedabove in connection with FIGS. 1, and 2-7. For example, the ring anodeelectrode 120 need not be placed around the perimeter of the device, butsuch electrode may be a flat circumferential electrode that assumesdifferent shapes (e.g., round or oval) that is placed on the front orback surface of the IEAD so as to surround the central electrode.Further, for some embodiments, the surfaces of the anode and cathodeelectrodes may have convex surfaces.

It is also noted that while one preferred embodiment has been disclosedherein that incorporates a round, or short cylindrical-shaped housing,also referred to as a coin-shaped housing, the invention does notrequire that the case 124 (which may also be referred to as a“container”), and its associated cover plate 122, be round. The casecould just as easily be an oval-shaped, rectangular-shaped (e.g., squarewith smooth corners), polygonal-shaped (e.g., hexagon-, octagon-,pentagon-shaped), button-shaped (with convex top or bottom for asmoother profile) device. Some particularly attractive alternate caseshapes, and electrode placement on the surfaces of those case shapes,are illustrated in Appendix E. Any of these alternate shapes, or others,would still permit the basic principles of the invention to be used toprovide a robust, compact, thin, case to house the electronic circuitryand power source used by the invention; as well as to help protect afeed-through assembly from being exposed to excessive heat duringassembly, and to allow the thin device to provide the benefits describedherein related to its manufacture, implantation and use. For example, aslong as the device remains relatively thin, e.g., no more than about 2-3mm, and does not have a maximum linear dimension greater than about 25mm, then the device can be readily implanted in a pocket over the tissuearea where the selected acupuoint(s) is located. As long as there is arecess in the wall around the perimeter of the case wherein thefeed-through assembly may be mounted, which recess effectively moves thewall or edge of the case inwardly into the housing a safe thermaldistance, as well as a safe residual weld stress distance, from theperimeter wall where a hermetically-sealed weld occurs, the principlesof the invention apply.

Further, it should be noted that while the preferred configuration ofthe IEAD described herein utilizes a central electrode on one of itssurfaces that is round, having a diameter of nominally 4 mm, suchcentral electrode need not necessarily be round. It could be ovalshaped, polygonal-shaped, or shaped otherwise, in which case its size isbest defined by its maximum width, which will generally be no greaterthan about 7 mm.

Finally, it is noted that the electrode arrangement may be modifiedsomewhat, and the desired attributes of the invention may still beachieved. For example, as indicated previously, one preferred electrodeconfiguration for use with the invention utilizes a symmetricalelectrode configuration, e.g., an annular electrode of a first polaritythat surrounds a central electrode of a second polarity. Such asymmetrical electrode configuration makes the implantableelectroacupuncture device (IEAD) relatively immune to being implanted inan improper orientation relative to the body tissue at the selectedacupoint(s) that is being stimulated. However, an electrodeconfiguration that is not symmetrical may still be used and many of thetherapeutic effects of the invention may still be achieved. For example,two spaced-apart electrodes on a front surface of the housing, one of afirst polarity, and a second of a second polarity, could still, whenoriented properly with respect to a selected acupoint tissue location,provide some desired therapeutic results

FIG. 7A schematically illustrates a few alternative electrodeconfigurations that may be used with the invention. The electrodeconfiguration schematically shown in the upper left corner of FIG. 7A,identified as “I”, schematically illustrates one central electrode 110surrounded by a single ring electrode 120. This is one of the preferredelectrode configurations that has been described previously inconnection, e.g., with the description of FIGS. 1, 1A, 1B and 7, and ispresented in FIG. 7A for reference and comparative purposes.

In the lower left corner of FIG. 7A, identified as “II”, anelectrode/array configuration is schematically illustrated that has acentral electrode 310 of a first polarity surrounded by an electrodearray 320 a of two electrodes of a second polarity. When the twoelectrodes (of the same polarity) in the electrode array 320 a areproperly aligned with the body tissue being stimulated, e.g., alignedwith a nerve 87 (see FIGS. 17A and 17B), then such electrodeconfiguration can stimulate the body tissue (e.g., the nerve 87) at ornear the desired acupoint(s) with the same, or almost the same, efficacyas can the electrode configuration I (upper right corner of FIG. 7A).

Note, as has already been described above, the phrase “electrode orelectrode array,” or “electrodes or electrode arrays,” may also bereferred to herein as “electrode/array” or “electrodes/arrays,”respectively. For the ease of explanation, when an electrode array isreferred to herein that comprises a plurality (two or more) ofindividual electrodes of the same polarity, the individual electrodes ofthe same polarity within the electrode array may also be referred to as“individual electrodes”, “segments” of the electrode array, “electrodesegments”, or just “segments”.

In the lower right corner of FIG. 7A, identified as “III”, en electrodeconfiguration is schematically illustrated that has a centralelectrode/array 310 b of three electrode segments of a first polaritysurrounded by an electrode array 320 b of three electrode segments of asecond polarity. As shown in FIG. 7A-III, the three electrode segmentsof the electrode array 320 b are symmetrically positioned within thearray 320 b, meaning that they are positioned more or less equidistantfrom each other. However, a symmetrical positioning of the electrodesegments within the array is not necessary to stimulate the body tissueat the desired acupoint(s) with some efficacy.

In the upper right corner of FIG. 7A, identified as “IV”, anelectrode/array configuration is schematically illustrated that has acentral electrode array 310 c of a first polarity surrounded by anelectrode array 320 c of four electrode segments of a second polarity.The four electrode segments of the electrode array 320 c are arrangedsymmetrically in a round or oval-shaped array. The four electrodesegments of the electrode array 310 b are likewise arrangedsymmetrically in a round or oval-shaped array. While preferred for manyconfigurations, the use of a symmetrical electrode/array, whether as acentral electrode array 310 or as a surrounding electrode/array 320, isnot always required.

The electrode configurations I, II, III and IV shown schematically inFIG. 7A are only representative of a few electrode configurations thatmay be used with the present invention. Further, it is to be noted thatthe central electrode/array 310 need not have the same number ofelectrode segments as does the surrounding electrode/array 320.Typically, the central electrode/array 310 of a first polarity will be asingle electrode; whereas the surrounding electrode/array 320 of asecond polarity may have n individual electrode segments, where n is aninteger that can vary from 1, 2, 3, . . . n. Thus, for a circumferentialelectrode array where n=4, there are four electrode segments of the samepolarity arranged in circumferential pattern around a centralelectrode/array. If the circumferential electrode array with n=4 is asymmetrical electrode array, then the four electrode segments will bespaced apart equally in a circumferential pattern around a centralelectrode/array. When n=1, the circumferential electrode array reducesto a single circumferential segment or a single annular electrode thatsurrounds a central electrode/array.

Additionally, the polarities of the electrode/arrays may be selected asneeded. That is, while the central electrode/array 310 is typically acathode (−), and the surrounding electrode/array 320 is typically ananode (+), these polarities may be reversed.

It should be noted that the shape of the circumferentialelectrode/array, whether circular, oval, or other shape, need notnecessarily be the same shape as the IEAD housing, unless thecircumferential electrode/array is attached to a perimeter edge of theIEAD housing. The IEAD housing may be round, or it may be oval, or itmay have a polygon shape, or other shape, as needed to suit the needs ofa particular manufacturer and/or patient.

Additional electrode configurations, both symmetrical electrodeconfigurations and non-symmetrical electrode configurations, that may beused with an EA stimulation device as described herein, are described inAppendix A and Appendix B.

II. E. Electrical Design

Next, with reference to FIGS. 8A-14, the electrical design and operationof the circuits employed within the IEAD 100 will be described. Moredetails associated with the design of the electrical circuits describedherein may be found in the following previously-filed U.S. ProvisionalPatent Applications, which applications are incorporated herein byreference: (1) Appl. No. 61/626,339, filed Sep. 23, 2011, entitledImplantable Electroacupuncture Device and Method for TreatingCardiovascular Disease; (2) Appl. No. 61/609,875, filed Mar. 12, 2012,entitled Boost Converter Output Control For ImplantableElectroacupuncture Device; (3) Appl. No. 61/672,257, filed Jul. 16,2012, entitled Boost Converter Circuit Surge Control For ImplantableElectroacupuncture Device Using Digital Pulsed Shutdown; (4) Appl. No.61/672,661, filed Jul. 17, 2012, entitled Smooth Ramp-Up StimulusAmplitude Control For Implantable Electroacupuncture Device; and (5)Appl. No. 61/674,691, filed Jul. 23, 2012, entitled Pulse ChargeDelivery Control In An Implantable Electroacupuncture Device.

FIG. 8A shows a functional block diagram of an implantableelectroacupuncture device (IEAD) 100 made in accordance with theteachings disclosed herein. As seen in FIG. 8A, the IEAD 100 uses animplantable battery 215 having a battery voltage V_(BAT). Also includedwithin the IEAD 100 is a Boost Converter circuit 200, an Output Circuit202 and a Control Circuit 210. The battery 115, boost converter circuit200, output circuit 202 and control circuit 210 are all housed within anhermetically sealed housing 124.

As controlled by the control circuit 210, the output circuit 202 of theIEAD 100 generates a sequence of stimulation pulses that are deliveredto electrodes E1 and E2, through feed-through terminals 206 and 207,respectively, in accordance with a prescribed stimulation regimen. Acoupling capacitor C_(C) is also employed in series with at least one ofthe feed-through terminals 206 or 207 to prevent DC (direct current)current from flowing into the patient's body tissue.

As explained more fully below in connection with the description ofFIGS. 15A and 15B, the prescribed stimulation regimen comprises acontinuous stream of stimulation pulses having a fixed amplitude, e.g.,V_(A) volts, a fixed pulse width, e.g., 0.5 millisecond, and at a fixedfrequency, e.g., 2 Hz, during each stimulation session. The stimulationsession, also as part of the stimulation regimen, is generated at a verylow duty cycle, e.g., for 30 minutes once each week. Other stimulationregimens may also be used, e.g., using a variable frequency for thestimulus pulse during a stimulation session rather than a fixedfrequency.

In one preferred embodiment, the electrodes E1 and E2 form an integralpart of the housing 124. That is, electrode E2 may comprise acircumferential anode electrode that surrounds a cathode electrode E1.The cathode electrode E1, for the embodiment described here, iselectrically connected to the case 124 (thereby making the feed-throughterminal 206 unnecessary).

In a second preferred embodiment, particularly well-suited forimplantable electrical stimulation devices, the anode electrode E2 iselectrically connected to the case 124 (thereby making the feed-throughterminal 207 unnecessary). The cathode electrode E1 is electricallyconnected to the circumferential electrode that surrounds the anodeelectrode E2. That is, the stimulation pulses delivered to the targettissue location (i.e., to the selected acupoint) through the electrodesE1 and E2 are, relative to a zero volt ground (GND) reference, negativestimulation pulses, as shown in the waveform diagram near the lowerright hand corner of FIG. 8A.

Thus, in the embodiment described in FIG. 8A, it is seen that during astimulation pulse the electrode E2 functions as an anode, or positive(+) electrode, and the electrode E1 functions as a cathode, or negative(−) electrode.

The battery 115 provides all of the operating power needed by the EAdevice 100. The battery voltage V_(BAT) is not the optimum voltageneeded by the circuits of the EA device, including the output circuitry,in order to efficiently generate stimulation pulses of amplitude, e.g.,−V_(A) volts. The amplitude V_(A) of the stimulation pulses is typicallymany times greater than the battery voltage V_(BAT). This means that thebattery voltage must be “boosted”, or increased, in order forstimulation pulses of amplitude V_(A) to be generated. Such “boosting”is done using the boost converter circuit 200. That is, it is thefunction of the Boost Converter circuit 200 to take its input voltage,V_(BAT), and convert it to another voltage, e.g., V_(OUT), which voltageV_(OUT) is needed by the output circuit 202 in order for the IEAD 100 toperform its intended function.

The IEAD 100 shown in FIG. 8A, and packaged as described above inconnection with FIGS. 1-7, advantageously provides a tinyself-contained, coin-sized stimulator that may be implanted in a patientat or near a specified acupoint in order to favorably treat a conditionor disease of a patient. The coin-sized stimulator advantageouslyapplies electrical stimulation pulses at very low levels and low dutycycles in accordance with specified stimulation regimens throughelectrodes that form an integral part of the housing of the stimulator.A tiny battery inside of the coin-sized stimulator provides enoughenergy for the stimulator to carry out its specified stimulation regimenover a period of several years. Thus, the coin-sized stimulator, onceimplanted, provides an unobtrusive, needleless, long-lasting, safe,elegant and effective mechanism for treating certain conditions anddiseases that have long been treated by acupuncture orelectroacupuncture.

A boost converter integrated circuit (IC) typically draws current fromits power source in a manner that is proportional to the differencebetween the actual output voltage V_(OUT) and a set point outputvoltage, or feedback signal. A representative boost converter circuitthat operates in this manner is shown in FIG. 8B. At boost converterstart up, when the actual output voltage is low compared to the setpoint output voltage, the current drawn from the power source can bequite large. Unfortunately, when batteries are used as power sources,they have internal voltage losses (caused by the battery's internalimpedance) that are proportional to the current drawn from them. Thiscan result in under voltage conditions when there is a large currentdemand from the boost converter at start up or at high instantaneousoutput current. Current surges and the associated under voltageconditions can lead to undesired behavior and reduced operating life ofan implanted electro-acupuncture device.

In the boost converter circuit example shown in FIG. 8A, the battery ismodeled as a voltage source with a simple series resistance. Withreference to the circuit shown in FIG. 8A, when the series resistanceR_(BAT) is small (5 Ohms or less), the boost converter input voltageV_(IN), output voltage V_(OUT) and current drawn from the battery,I_(BAT), typically look like the waveform shown in FIG. 9A, where thehorizontal axis is time, and the vertical axis on the left is voltage,and the vertical axis of the right is current.

Referring to the waveform in FIG. 9A, at boost converter startup (10ms), there is 70 mA of current drawn from the battery with only ˜70 mVof drop in the input voltage V_(IN). Similarly, the instantaneous outputcurrent demand for electro-acupuncture pulses draws up to 40 mA from thebattery with an input voltage drop of ˜40 mV.

Disadvantageously, however, a battery with higher internal impedance(e.g., 160 Ohms), cannot source more than a milliampere or so of currentwithout a significant drop in output voltage. This problem is depictedin the timing waveform diagram shown in FIG. 9B. In FIG. 9B, as in FIG.9A, the horizontal axis is time, the left vertical axis is voltage, andthe right vertical axis is current.

As seen in FIG. 9B, as a result of the higher internal batteryimpedance, the voltage at the battery terminal (V_(IN)) is pulled downfrom 2.9 V to the minimum input voltage of the boost converter (˜1.5 V)during startup and during the instantaneous output current loadassociated with electro-acupuncture stimulus pulses. The resulting dropsin output voltage V_(OUT) are just not acceptable in any type of circuitexcept an uncontrolled oscillator circuit.

Also, it should be noted that although the battery used in the boostconverter circuit is modeled in FIG. 8B as a simple series resistor,battery impedance can arise from the internal design, battery electrodesurface area and different types of electrochemical reactions. All ofthese contributors to battery impedance can cause the voltage of thebattery at the battery terminals to decrease as the current drawn fromthe battery increases.

In a suitably small and thin implantable electroacupuncture device(IEAD) of the type disclosed herein, it is desired to use a higherimpedance battery in order to assure a small and thin device, keep costslow, and/or to have low self-discharge rates. The battery internalimpedance also typically increases as the battery discharges. This canlimit the service life of the device even if a new battery hasacceptably low internal impedance. Thus, it is seen that for the IEAD100 disclosed herein to reliably perform its intended function over along period of time, a circuit design is needed for the boost convertercircuit that can manage the instantaneous current drawn from V_(IN) ofthe battery. Such current management is needed to prevent the battery'sinternal impedance from causing V_(IN) to drop to unacceptably lowlevels as the boost converter circuit pumps up the output voltageV_(OUT) and when there is high instantaneous output current demand, asoccurs when EA stimulation pulses are generated.

To provide this needed current management, the IEAD 100 disclosed hereinemploys electronic circuitry as shown in FIG. 10, or equivalentsthereof. Similar to what is shown in FIG. 8B, the circuitry of FIG. 10includes a battery, a boost converter circuit 200, an output circuit230, and a control circuit 220. The control circuit 220 generates adigital control signal that is used to duty cycle the boost convertercircuit 200 ON and OFF in order to limit the instantaneous current drawnfrom the battery. That is, the digital control signal pulses the boostconverter ON for a short time, but then shuts the boost converter downbefore a significant current can be drawn from the battery. Inconjunction with such pulsing, an input capacitance C_(F) is used toreduce the ripple in the input voltage V_(IN). The capacitor C_(F)supplies the high instantaneous current for the short time that theboost converter is ON and then recharges more slowly from the batteryduring the interval that the boost converter is OFF.

In the circuitry shown in FIG. 10, it is noted that the output voltageV_(OUT) generated by the boost converter circuit 200 is set by thereference voltage V_(REF) applied to the set point or feedback terminalof the boost converter circuit 200. For the configuration shown in FIG.10, V_(REF) is proportional to the output voltage V_(OUT), as determinedby the resistor dividing network of R1 and R2.

The switches S_(P) and S_(R), shown in FIG. 10 as part of the outputcircuit 230, are also controlled by the control circuit 220. Theseswitches are selectively closed and opened to form the EA stimulationpulses applied to the load, R_(LOAD). Before a stimulus pulse occurs,switch S_(R) is closed sufficiently long for the circuit side ofcoupling capacitor C_(C) to be charged to the output voltage, V_(OUT).The tissue side of C_(C) is maintained at 0 volts by the cathodeelectrode E2, which is maintained at ground reference. Then, for most ofthe time between stimulation pulses, both switches S_(R) and S_(P) arekept open, with a voltage approximately equal to the output voltageV_(OUT) appearing across the coupling capacitor C_(C).

At the leading edge of a stimulus pulse, the switch Sp is closed, whichimmediately causes a negative voltage −V_(OUT) to appear across theload, R_(LOAD), causing the voltage at the anode E1 to also drop toapproximately −V_(OUT), thereby creating the leading edge of thestimulus pulse. This voltage starts to decay back to 0 volts ascontrolled by an RC (resistor-capacitance) time constant that is longcompared with the desired pulse width. At the trailing edge of thepulse, before the voltage at the anode E1 has decayed very much, theswitch S_(P) is open and the switch S_(R) is closed. This action causesthe voltage at the anode E1 to immediately (relatively speaking) returnto 0 volts, thereby defining the trailing edge of the pulse. With theswitch S_(R) closed, the charge on the circuit side of the couplingcapacitor C_(c) is allowed to charge back to V_(OUT) within a timeperiod controlled by a time constant set by the values of capacitorC_(C) and resistor R3. When the circuit side of the coupling capacitorC_(c) has been charged back to V_(OUT), then switch S_(R) is opened, andboth switches S_(R) and S_(P) remain open until the next stimulus pulseis to be generated. Then the process repeats each time a stimulus pulseis to be applied across the load.

Thus, it is seen that in one embodiment of the electronic circuitry usedwithin the IEAD 100, as shown in FIG. 10, a boost converter circuit 200is employed which can be shut down with a control signal. The controlsignal is ideally a digital control signal generated by a controlcircuit 220 (which may be realized using a microprocessor or equivalentcircuit). The control signal is applied to the low side (ground side) ofthe boost converter circuit 200 (identified as the “shutdown” terminalin FIG. 10). A capacitor C_(F) supplies instantaneous current for theshort ON time that the control signal enables the boost convertercircuit to operate. And, the capacitor CF is recharged from the batteryduring the relatively long OFF time when the control signal disables theboost converter circuit.

An alternate embodiment of the electronic circuitry that may be usedwithin the IDEA 100 is shown in FIG. 11. This circuit is in mostrespects the same as the circuitry shown in FIG. 10. However, in thisalternate embodiment shown in FIG. 11, the boost converter circuit 200does not have a specific shut down input control. Rather, as seen inFIG. 11, the boost converter circuit is shut down by applying a controlvoltage to the feedback input of the boost converter circuit 200 that ishigher than V_(REF). When this happens, i.e., when the control voltageapplied to the feedback input is greater than V_(REF), the boostconverter will stop switching and draws little or no current from thebattery. The value of V_(REF) is typically a low enough voltage, such asa 1.2 V band-gap voltage, that a low level digital control signal can beused to disable the boost converter circuit. To enable the boostconverter circuit, the control signal can be set to go to a highimpedance, which effectively returns the node at the V_(REF) terminal tothe voltage set by the resistor divider network formed from R1 and R2.Alternatively the control signal can be set to go to a voltage less thanV_(REF).

A low level digital control signal that performs this function ofenabling (turning ON) or disabling (turning OFF) the boost convertercircuit is depicted in FIG. 11 as being generated at the output of acontrol circuit 220. The signal line on which this control signal ispresent connects the output of the control circuit 220 with the V_(REF)node connected to the feedback input of the boost converter circuit.This control signal, as suggested by the waveform shown in FIG. 11,varies from a voltage greater than V_(REF), thereby disabling or turningOFF the boost converter circuit, to a voltage less than V_(REF), therebyenabling or turning the boost converter circuit ON.

A refinement to the alternate embodiment shown in FIG. 11 is to use thecontrol signal to drive the low side of R2 as shown in FIG. 12. That is,as shown in FIG. 12, the boost converter circuit 200 is shut down whenthe control signal is greater than V_(REF) and runs when the controlsignal is less than V_(REF). A digital control signal can be used toperform this function by switching between ground and a voltage greaterthan V_(REF). This has the additional possibility of delta-sigmamodulation control of V_(OUT) if a measurement of the actual V_(OUT) isavailable for feedback, e.g., using a signal line 222, to thecontroller.

One preferred embodiment of the circuitry used in an implantableelectroacupuncture device (IEAD) 100 that employs a digital controlsignal as taught herein is shown in the schematic diagram shown in FIG.13A. In FIG. 13A, there are basically four integrated circuits (ICs)used as the main components. The IC U1 is a boost converter circuit, andperforms the function of the boost converter circuit 200 describedpreviously in connection with FIGS. 8B, 10, 11 and 12.

The IC U2 is a micro-controller IC and is used to perform the functionof the control circuit 220 described previously in connection with FIGS.10, 11 and 12. A preferred IC for this purpose is a MSP430G2452Imicro-controller chip made by Texas Instruments. This chip includes 8 KBof Flash memory. Having some memory included with the micro-controlleris important because it allows the parameters associated with a selectedstimulation regimen to be defined and stored. One of the advantages ofthe IEAD described herein is that it provides a stimulation regimen thatcan be defined with just 5 parameters, as taught below in connectionwith FIGS. 15A and 15B. This allows the programming features of themicro-controller to be carried out in a simple and straightforwardmanner.

The micro-controller U2 primarily performs the function of generatingthe digital signal that shuts down the boost converter to prevent toomuch instantaneous current from being drawn from the battery V_(BAT).The micro-controller U2 also controls the generation of the stimuluspulses at the desired pulse width and frequency. It further keeps trackof the time periods associated with a stimulation session, i.e., when astimulation session begins and when it ends.

The micro-controller U2 also controls the amplitude of the stimuluspulse. This is done by adjusting the value of a current generated by aProgrammable Current Source U3. In one embodiment, U3 is realized with avoltage controlled current source IC. In such a voltage controlledcurrent source, the programmed current is set by a programmed voltageappearing across a fixed resistor R5, i.e., the voltage appearing at the“OUT” terminal of U3. This programmed voltage, in turn, is set by thevoltage applied to the “SET” terminal of U3. That is, the programmedcurrent source U3 sets the voltage at the “OUT” terminal to be equal tothe voltage applied to the “SET” terminal. The programmed current thatflows through the resistor R5 is then set by Ohms Law to be the voltageat the “set” terminal divided by R5. As the voltage at the “set”terminal changes, the current flowing through resistor R5 at the “OUT”terminal changes, and this current is essentially the same as thecurrent pulled through the closed switch M1, which is essentially thesame current flowing through the load R_(LOAD). Hence, whatever currentflows through resistor R₅, as set by the voltage across resistor R₅, isessentially the same current that flows through the load R_(LOAD). Thus,as the micro-controller U2 sets the voltage at the “set” terminal of U3,on the signal line labeled “AMPSET”, it controls what current flowsthrough the load R_(LOAD). In no event can the amplitude of the voltagepulse developed across the load R_(LOAD) exceed the voltage V_(OUT)developed by the boost converter less the voltage drops across theswitches and current source.

The switches S_(R) and S_(P) described previously in connection withFIGS. 10, 11 and 12 are realized with transistor switches M1, M2, M3,M4, M5 and M6, each of which is controlled directly or indirectly bycontrol signals generated by the micro-controller circuit U2. For theembodiment shown in FIG. 13A, these switches are controlled by twosignals, one appearing on signal line 234, labeled PULSE, and the otherappearing on signal line 236, labeled RCHG (which is an abbreviation for“recharge”). For the circuit configuration shown in FIG. 13A, the RCHGsignal on signal line 236 is always the inverse of the PULSE signalappearing on signal line 234. This type of control does not allow bothswitch M1 and switch M2 to be open or closed at the same time. Rather,switch M1 is closed when switch M2 is open, and switch M2 is closed,when switch M1 is open. When switch M1 is closed, and switch M2 is open,the stimulus pulse appears across the load, R_(LOAD), with the currentflowing through the load, R_(LOAD), being essentially equal to thecurrent flowing through resistor R₅. When the switch M1 is open, andswitch M2 is closed, no stimulus pulse appears across the load, and thecoupling capacitors C5 and C6 are recharged through the closed switch M2and resistor R6 to the voltage V_(OUT) in anticipation of the nextstimulus pulse.

The circuitry shown in FIG. 13A is only exemplary of one type of circuitthat may be used to control the pulse width, amplitude, frequency, andduty cycle of stimulation pulses applied to the load, R_(LOAD). Any typeof circuit, or control, that allows stimulation pulses of a desiredmagnitude (measured in terms of pulse width, frequency and amplitude,where the amplitude may be measured in current or voltage) to be appliedthrough the electrodes to the patient at the specified acupoint at adesired duty cycle (stimulation session duration and frequency) may beused. However, for the circuitry to perform its intended function over along period of time, e.g., years, using only a small energy source,e.g., a small coin-sized battery having a high battery impedance and arelatively low capacity, the circuitry must be properly managed andcontrolled to prevent excessive current draw from the battery.

It is also important that the circuitry used in the IEAD 100, e.g., thecircuitry shown in FIGS. 10, 11, 12, 13A, or equivalents thereof, havesome means for controlling the stimulation current that flows throughthe load, R_(LOAD), which load may be characterized as the patient'stissue impedance at and around the acupoint being stimulated. Thistissue impedance, as shown in FIGS. 11 and 12, may typically vary frombetween about 300 ohms to 2000 ohms. Moreover, it not only varies fromone patient to another, but it varies over time. Hence, there is a needto control the current that flows through this variable load, R_(LOAD).One way of accomplishing this goal is to control the stimulationcurrent, as opposed to the stimulation voltage, so that the same currentwill flow through the tissue load regardless of changes that may occurin the tissue impedance over time. The use of a voltage controlledcurrent source U3, as shown in FIG. 13A, is one way to satisfy thisneed.

Still referring to FIG. 13A, a fourth IC U4 is connected to themicro-controller U2. For the embodiment shown in FIG. 13A, the IC U4 isan electromagnetic field sensor, and it allows the presence of anexternally-generated (non-implanted) electromagnetic field to be sensed.An “electromagnetic” field, for purposes of this application includesmagnetic fields, radio frequency (RF) fields, light fields, and thelike. The electromagnetic sensor may take many forms, such as anywireless sensing element, e.g., a pickup coil or RF detector, a photondetector, a magnetic field detector, and the like. When a magneticsensor is employed as the electromagnetic sensor U4, the magnetic fieldis generated using an External Control Device (ECD) 240 thatcommunicates wirelessly, e.g., through the presence or absence of amagnetic field, with the magnetic sensor U4. (A magnetic field, or othertype of field if a magnetic field is not used, is symbolicallyillustrated in FIG. 13A by the wavy line 242.) In its simplest form, theECD 240 may simply be a magnet, and modulation of the magnetic field isachieved simply by placing or removing the magnet next to or away fromthe IEAD. When other types of sensors (non-magnetic) are employed, theECD 240 generates the appropriate signal or field to be sensed by thesensor that is used.

Use of the ECD 240 provides a way for the patient, or medical personnel,to control the IEAD 100 after it has been implanted (or before it isimplanted) with some simple commands, e.g., turn the IEAD ON, turn theIEAD OFF, increase the amplitude of the stimulation pulses by oneincrement, decrease the amplitude of the stimulation pulses by oneincrement, and the like. A simple coding scheme may be used todifferentiate one command from another. For example, one coding schemeis time-based. That is, a first command is communicated by holding amagnet near the IEAD 100, and hence near the magnetic sensor U4contained within the IEAD 100, for differing lengths of time. If, forexample, a magnet is held over the IEAD for at least 2 seconds, but nomore than 7 seconds, a first command is communicated. If a magnet isheld over the IEAD for at least 11 seconds, but no more than 18 seconds,a second command is communicated, and so forth.

Another coding scheme that could be used is a sequence-based codingscheme. That is, application of 3 magnetic pulses may be used to signalone external command, if the sequence is repeated 3 times. A sequence of2 magnetic pulses, repeated twice, may be used to signal anotherexternal command. A sequence of one magnetic pulse, followed by asequence of two magnetic pulses, followed by a sequence of threemagnetic pulses, may be used to signal yet another external command.

Other simple coding schemes may also be used, such as the letters AA,RR, HO, BT, KS using international Morse code. That is, the Morse codesymbols for the letter “A” are dot dash, where a dot is a short magneticpulse, and a dash is a long magnetic pulse. Thus, to send the letter Ato the IEAD 100 using an external magnet, the user would hold the magnetover the area where the IEAD 100 is implanted for a short period oftime, e.g., one second or less, followed by holding the magnet over theIEAD for a long period of time, e.g., more than one second.

More sophisticated magnetic coding schemes may be used to communicate tothe micro-controller chip U2 the operating parameters of the IEAD 100.For example, using an electromagnet controlled by a computer, the pulsewidth, frequency, and amplitude of the EA stimulation pulses used duringeach stimulation session may be pre-set. Also, the frequency of thestimulation sessions can be pre-set. Additionally, a master reset signalcan be sent to the device in order to re-set these parameters to defaultvalues. These same operating parameters and commands may be re-sent atany time to the IEAD 100 during its useful lifetime should changes inthe parameters be desired or needed.

The current and voltage waveforms associated with the operation of thelEAD circuitry of FIG. 13A are shown in FIG. 13B. In FIG. 13B, thehorizontal axis is time, the left vertical axis is voltage, and theright vertical axis is current. The battery in this example has 160 Ohmsof internal impedance.

Referring to FIGS. 13A and 13B, during startup, the boost converter ONtime is approximately 30 microseconds applied every 7.8 milliseconds.This is sufficient to ramp the output voltage V_(OUT) up to over 10 Vwithin 2 seconds while drawing no more than about 1 mA from the batteryand inducing only 150 mV of input voltage ripple.

The electroacupuncture (EA) simulation pulses resulting from operationof the circuit of FIG. 13A have a width of 0.5 milliseconds and increasein amplitude from approximately 1 mA in the first pulse to approximately15 mA in the last pulse. The instantaneous current drawn from thebattery is less than 2 mA for the EA pulses and the drop in batteryvoltage is less than approximately 300 mV. The boost converter isenabled (turned ON) only during the instantaneous output current surgesassociated with the 0.5 milliseconds wide EA pulses.

Another preferred embodiment of the circuitry used in an implantableelectroacupuncture device (IEAD) 100 that employs a digital controlsignal as taught herein is shown in the schematic diagram of FIG. 14.The circuit shown in FIG. 14 is, in most respects, very similar to thecircuit described previously in connection with FIG. 13A. What is new inFIG. 14 is the inclusion of an external Schottky diode D4 at the outputterminal LX of the boost convertor U1 and the inclusion of a fifthintegrated circuit (IC) U5 that essentially performs the same functionas the switches M1-M6 shown in FIG. 13A.

The Schottky diode D5 helps isolate the output voltage V_(OUT) generatedby the boost converter circuit U1. This is important in applicationswhere the boost converter circuit U1 is selected and operated to providean output voltage V_(OUT) that is four or five times as great as thebattery voltage, V_(BAT). For example, in the embodiment for which thecircuit of FIG. 14 is designed, the output voltage V_(OUT) is designedto be nominally 15 volts using a battery that has a nominal batteryvoltage of only 3 volts. (In contrast, the embodiment shown in FIG. 13Ais designed to provide an output voltage that is nominally 10-12 volts,using a battery having a nominal output voltage of 3 volts.)

The inclusion of the fifth IC U5 in the circuit shown in FIG. 14 is, asindicated, used to perform the function of a switch. The other ICs shownin FIG. 14, U1 (boost converter), U2 (micro-controller), U3 (voltagecontrolled programmable current source) and U4 (electromagnetic sensor)are basically the same as the IC's U1, U2, U3 and U4 describedpreviously in connection with FIG. 13A.

The IC U5 shown in FIG. 14 functions as a single pole/double throw(SPDT) switch. Numerous commercially-available ICs may be used for thisfunction. For example, an ADG1419 IC, available from Analog DevicesIncorporated (ADI) may be used. In such IC U5, the terminal “D”functions as the common terminal of the switch, and the terminals “SA”and “SB” function as the selected output terminal of the switch. Theterminals “IN” and “EN” are control terminals to control the position ofthe switch. Thus, when there is a signal present on the PULSE line,which is connected to the “IN” terminal of U5, the SPDT switch U5connects the “D” terminal to the “SB” terminal, and the SPDT switch U5effectively connects the cathode electrode E1 to the programmablecurrent source U3. This connection thus causes the programmed current,set by the control voltage AMPSET applied to the SET terminal of theprogrammable current source U3, to flow through resistor R₅, which inturn causes essentially the same current to flow through the load,R_(LOAD), present between the electrodes E1 and E2. When a signal is notpresent on the PULSE line, the SPDT switch U5 effectively connects thecathode electrode E1 to the resistor R6, which allows the couplingcapacitors C12 and C13 to recharge back to the voltage V_(OUT) providedby the boost converter circuit U2.

From the above description, it is seen that an implantable IEAD 100 isprovided that uses a digital control signal to duty-cycle limit theinstantaneous current drawn from the battery by a boost converter. Threedifferent exemplary configurations (FIGS. 10, 11 and 12) are taught forachieving this desired result, and two exemplary circuit designs thatmay be used to realize this result have been disclosed (FIGS. 13A and14). One configuration (FIG. 12) teaches the additional capability todelta-sigma modulate the boost converter output voltage.

Delta-sigma modulation is well described in the art. Basically, it is amethod for encoding analog signals into digital signals orhigher-resolution digital signals into lower-resolution digital signals.The conversion is done using error feedback, where the differencebetween the two signals is measured and used to improve the conversion.The low-resolution signal typically changes more quickly than thehigh-resolution signal and it can be filtered to recover the highresolution signal with little or no loss of fidelity. Delta-sigmamodulation has found increasing use in modern electronic components suchas converters, frequency synthesizers, switched-mode power supplies andmotor controllers. See, e.g., Wikipedia, Delta-sigma modulation.

II. F. Use and Operation

With the implantable electroacupuncture device (IDEA) 100 in hand, theIDEA 100 may be used most effectively to treat mental illness by firstpre-setting stimulation parameters that the device will use during astimulation session. FIG. 15A shows a timing waveform diagramillustrating the EA stimulation parameters used by the IEAD to generateEA stimulation pulses. As seen in FIG. 15A, there are basically fourparameters associated with a stimulation session. The time T1 definesthe duration (or pulse width) of a stimulus pulse. The time T2 definesthe time between the start of one stimulus pulse and the start of thenext stimulus pulse. The time T2 thus defines the period associated withthe frequency of the stimulus pulses. The frequency of the stimulationpulses is equal to 1/T2. The ratio of T1/T2 is typically quite low,e.g., less than 0.01. The duration of a stimulation session is definedby the time period T3. The amplitude of the stimulus pulses is definedby the amplitude A1. This amplitude may be expressed in either voltageor current.

Turning next to FIG. 15B, a timing waveform diagram is shown thatillustrates the manner in which the stimulation sessions areadministered in accordance with a preferred stimulation regimen. FIG.15B shows several stimulation sessions of duration T3, and how often thestimulation sessions occur. The stimulation regimen thus includes a timeperiod T4 which sets the time period from the start of one stimulationsession to the start of the next stimulation session. T4 thus is theperiod of the stimulation session frequency, and the stimulation sessionfrequency is equal to 1/T4.

One preferred set of parameters to use to define a stimulation regimenare

T1=0.5 milliseconds

T2=500 milliseconds

T3=60 minutes

T4=7 days (10,080 minutes)

A1=6 volts (across 1 kOhm), or 6 milliamperes (mA)

It is to be emphasized that the values shown above for the stimulationregimen are representative of only one preferred stimulation regimenthat could be used. Other stimulation regimens that could be used, andthe ranges of values that could be used for each of these parameters,are as defined in the claims.

It is also emphasized that the ranges of values presented in the claimsfor the parameters used with the invention have been selected after manymonths of careful research and study, and are not arbitrary. Forexample, the ratio of T3/T4, which sets the duty cycle, has beencarefully selected to be very low, e.g., no more than 0.05. Maintaininga low duty cycle of this magnitude represents a significant change overwhat others have attempted in the implantable stimulator art. Not onlydoes a very low duty cycle allow the battery itself to be small (coincell size), which in turn allows the IEAD housing to be very small,which makes the IEAD ideally suited for being used without leads,thereby making it relatively easy to implant the device at the desiredacupuncture site, but it also limits the frequency and duration ofstimulation sessions.

Limiting the frequency and duration of the stimulation sessions is a keyaspect of applicants' invention because it recognizes that sometreatments, such as treating mental illness, are best done slowly andmethodically, over time, rather than quickly and harshly using largedoses of stimulation (or other treatments) aimed at forcing a rapidchange in the patient's condition. Moreover, applying treatments slowlyand methodically is more in keeping with traditional acupuncture methods(which, as indicated previously, are based on over 2500 years ofexperience). In addition, this slow and methodical conditioning isconsistent with the time scale for remodeling of the central nervoussystem needed to produce the sustained therapeutic effect. Thus,applicants have based their treatment regimens on theslow-and-methodical approach, as opposed to the immediate-and-forcedapproach adopted by many, if not most, prior art implantable electricalstimulators.

Once the stimulation regimen has been defined and the parametersassociated with it have been pre-set into the memory of themicro-controller circuit 220, the IEAD 100 needs to be implanted.Implantation is usually a simple procedure, and is described above inconnection with the description of FIGS. 1A and 1B, as well as FIGS. 17Aand 17B.

For treating the specific mental illnesses targeted by this embodimentof the invention, i.e., depression, bipolar disorder and Anxiety, thespecified acupoint(s) (or target tissue locations) at which the EAstimulation pulses should be applied in accordance with a selectedstimulation regimen are the acupoints GV20 and/or EXHN3, or theirunderlying nerves. As indicated previously, acupoint GV20 is located onthe head at the midpoint of the connecting line between the auricularapices. It is also about 4.5 inches superior to the anterior hairline onthe anterior median line. See FIG. 1B and Appendix D. Acupoint EXHN3,also referred to herein as acupoint GV24.5, is located on the foreheadat the midpoint between the two medial ends of the eyebrow. See FIG. 1Aand Appendix D.

After implantation, the IEAD must be turned ON, and otherwisecontrolled, so that the desired stimulation regimen may be carried out.In one preferred embodiment, control of the IEAD after implantation, aswell as anytime after the housing of the IEAD has been hermeticallysealed, is performed as shown in the state diagram of FIG. 16. Eachcircle shown in FIG. 16 represents a “state” that the micro-controllerU2 (in FIG. 13A or 14) may operate in under the conditions specified. Asseen in FIG. 16, the controller U2 only operates in one of six states:(1) a “Set Amplitude” state, (2) a “Shelf Mode” state, (3) a “TriggeredSession” state, (4) a “Sleep” state, (5) an “OFF” state, and an (6)“Automatic Session” state. The “Automatic Session” state is the statethat automatically carries out the stimulation regimen using thepre-programmed parameters that define the stimulation regimen.

Shelf Mode is a low power state in which the IEAD is placed prior toshipment. After implant, commands are made through magnet application.Magnet application means an external magnet, typically a small hand-heldcylindrical magnet, is placed over the location where the IEAD has beenimplanted. With a magnet in that location, the magnetic sensor U4 sensesthe presence of the magnet and notifies the controller U2 of themagnet's presence.

From the “Shelf Mode” state, a magnet application for 10 seconds (M.10s)puts the IEAD in the “Set Amplitude” state. While in the “Set Amplitude”state, the stimulation starts running by generating pulses at zeroamplitude, incrementing every five seconds until the patient indicatesthat a comfortable level has been reached. At that time, the magnet isremoved to set the amplitude.

If the magnet is removed and the amplitude is non-zero ( M

A), the device continues into the “Triggered Session” so the patientreceives the initial therapy. If the magnet is removed during “SetAmplitude” while the amplitude is zero ( M

A), the device returns to the Shelf Mode.

The Triggered Session ends and stimulation stops after the session time(T_(S)) has elapsed and the device enters the “Sleep” state. If a magnetis applied during a Triggered Session (M), the session aborts to the“OFF” state. If the magnet remains held on for 10 seconds (M.10s) whilein the “OFF” state, the “Set Amplitude” state is entered with thestimulation level starting from zero amplitude as described.

If the magnet is removed ( M) within 10 seconds while in the OFF state,the device enters the Sleep state. From the Sleep state, the deviceautomatically enters the Automatic Session state when the sessioninterval time has expired (T_(I)). The Automatic Session deliversstimulation for the session time (T_(S)) and the device returns to theSleep state. In this embodiment, the magnet has no effect once theAutomatic Session starts so that the full therapy session is delivered.

While in the Sleep state, if a magnet has not been applied in the last30 seconds (D) and a magnet is applied for a window between 20-25seconds and then removed (M.20:25s), a Triggered Session is started. Ifthe magnet window is missed (i.e. magnet removed too soon or too late),the 30 second de-bounce period (D) is started. When de-bounce is active,no magnet must be detected for 30 seconds before a Triggered Session canbe initiated.

The session interval timer runs while the device is in Sleep state. Thesession interval timer is initialized when the device is woken up fromShelf Mode and is reset after each session is completely delivered. Thusabort of a triggered session by magnet application will not reset thetimer, the Triggered Session must be completely delivered.

The circuitry that sets the various states shown in FIG. 16 as afunction of externally-generated magnetic control commands, or otherexternally-generated command signals, is the micro-controller U2 (FIG.14), the processor U2 (FIG. 13A), or the control circuit 220 (FIGS. 10,11 and 12). Such processor-type circuits are programmable circuits thatoperate as directed by a program. The program is often referred to as“code”, or a sequence of steps that the processor circuit follows. The“code” can take many forms, and be written in many different languagesand formats, known to those of skill in the art. Representative “code”for the micro-controller U2 (FIG. 14) for controlling the states of theIEAD as shown in FIG. 16 is found in Appendix C, attached hereto, andincorporated by reference herein.

In the preceding description, various exemplary embodiments have beendescribed with reference to the accompanying drawings. It will, however,be evident that various modifications and changes may be made thereto,and additional embodiments may be implemented, without departing fromthe scope of the invention as set forth in the claims that follow. Forexample, certain features of one embodiment described herein may becombined with or substituted for features of another embodimentdescribed herein. The description and drawings are accordingly to beregarded in an illustrative rather than a restrictive sense and are notintended to be exhaustive or to limit the invention to any precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching. Thus, while the invention(s) herein disclosed hasbeen described by means of specific embodiments and applicationsthereof, numerous modifications and variations could be made thereto bythose skilled in the art without departing from the scope of theinvention(s) set forth in the claims.

What is claimed is:
 1. An Implantable ElectroAcupuncture System (IEAS)for treating depression and similar mental conditions throughapplication of electroacupuncture (EA) stimulation pulses applied at aspecified tissue location of a patient, comprising: an implantableelectroacupuncture (EA) device comprising a small, hermetically-sealedhousing containing a primary power source, pulse generation circuitrypowered by the primary power source, and a sensor that wirelessly sensesoperating commands generated external to the housing, wherein the pulsegeneration circuitry generates stimulation pulses in accordance with aspecified stimulation regimen as controlled at least in part by theoperating commands sensed through the sensor; a plurality of electrodearrays, where an electrode array comprises an array of n conductivecontacts electrically joined together to function jointly as oneelectrode, where n is an integer, on the outside of the EA devicehousing electrically coupled to the pulse generation circuitry on theinside of the EA device housing through at least one feed-throughterminal passing through a wall of the hermetically-sealed housing,whereby the stimulation pulses generated by the pulse generationcircuitry are directed to the electrode arrays on the outside of the EAdevice housing, where the electrical pulses are applied at the specifiedtissue location through the plurality of electrode arrays in accordancewith the specified stimulation regimen; wherein the specifiedstimulation regimen defines how often a stimulation session comprising astream of stimulation pulses is applied to the patient, the stimulationregimen requiring that the stimulation session have a duration of T3minutes and a rate of occurrence of once every T4 minutes, wherein theratio of T3/T4 is no greater than 0.05; and wherein the specified tissuelocation at which EA stimulation pulses are applied comprises at leastone of acupoints GV20 and EXHN3, or their underlying nerves, or at leastone of the tree branches of the Trigeminal nerve known as thesupratrochlear, supraorbital and infraorbital nerves.
 2. The IEAS ofclaim 1 wherein at least one of the plurality of electrode arrays islocated at the distal end of a short pigtail lead attached to the EAdevice.
 3. The IEAS of claim 1 wherein the plurality of electrode arraysare located on an outside surface of the case of the implantable EAdevice.
 4. The IEAS of claim 3 wherein the plurality of electrode arraysare located on a bottom surface of the case of the implantable EAdevice.
 5. The IEAS of claim 4 wherein a first one of the plurality ofelectrode arrays is centrally located on the bottom surface of the caseof the implantable EA device and a second one of the plurality ofelectrode arrays surrounds the first array.
 6. The IEAS of claim 1wherein the dimensions of the EA device are L×W×H, where L is thelongest linear dimension, W is the shortest linear dimension measured insubstantially the same plane as L, and H is the maximum height orthickness of the housing measured in a plane orthogonal with the planewhere L and W are measured, and wherein L is no greater than about 25mm, W is no less than about 15 mm and H is no greater than about 3 mm.7. The IEAS of claim 1 wherein the primary power source of the EA devicecomprises a battery having a nominal output voltage of no more than 3.0volts and an internal impedance of no less than about 5 ohms.
 8. TheIEAS of claim 7 wherein the pulse generation circuitry includes: a boostconverter circuit that boosts the nominal voltage of the primary batteryto an output voltage V_(OUT) that is at least three times the nominalbattery voltage; a control circuit that selectively turns the boostconverter circuit OFF and ON to limit the amount of current that may bedrawn from the primary battery; and an output circuit powered by V_(OUT)and controlled by the control circuit that generates the stimulationpulses as defined by the specified stimulation regimen.
 9. The IEAS ofclaim 8 wherein the stimulation pulses generated by the pulse generationcircuit and delivered through the plurality of electrode arrays into aload at the specified tissue location comprise voltage pulses having avoltage amplitude of no less than about 1 V and no greater than about 15V.
 10. The IEAS of claim 8 wherein the stimulation pulses generated bythe pulse generation circuit and delivered through the plurality ofelectrode arrays into a load at the specified tissue location comprisecurrent pulses having a current amplitude of no less than about 1milliampere (mA) and no greater than about 15 mA.
 11. The IEAS of claim10 wherein the primary battery has sufficient capacity to power thepulse generation circuitry in accordance with the specified stimulationregimen for a minimum of 2 years.
 12. The IEAS of claim 1 wherein theduration of the stimulation session T3 varies between 20 minutes and 72minutes if the rate of occurrence of the stimulation session T4 is setto a value between 1,440 minutes and 20,160 minutes [14 days]; andwherein T3 varies between 10 minutes and a maximum T3 value, T3(max) ifT4 is set to a value between 720 minutes and 1,440 minutes, wherein thevalue of T3(max) varies as a function of T4 as defined by the equation:T3(max)=0.05*T4.
 13. The IEAS of claim 1 further including an externalcontrol device adapted to selectively generate operating commands thatare sensed by the sensor within the implantable EA device.
 14. The IEASof claim 13 wherein the sensor within the implantable EA devicecomprises a magnetic field sensor, and wherein the external controldevice comprises a magnet.
 15. An Implantable ElectroAcupuncture System(IEAS) for treating depression and similar mental conditions of apatient, comprising a) an implantable electroacupuncture (EA) devicehousing having a maximum linear dimension of no more than 25 mm in afirst plane, and a maximum height of no more 2.5 mm in a second planeorthogonal to the first plane; b) a primary battery within the EAhousing having an internal impedance of no less than about 5 ohms; c)pulse generation circuitry within the EA housing and powered by theprimary battery that generates stimulation pulses during a stimulationsession; d) control circuitry within the EA housing and powered by theprimary battery that controls the frequency of the stimulation sessionsto occur no more than once every T4 minutes, and that further controlsthe duration of each stimulation session to last no longer than T3minutes, where the ratio of T3/T4 is no greater than 0.05; e) sensorcircuitry within the EA housing and coupled to the control circuitrythat is responsive to the presence of a control command generatedexternal to the EA device housing, which control command when receivedby the control circuitry sets the times T3 and T4 to appropriate values;and f) a plurality of electrodes located outside of the EA devicehousing that are electrically coupled to the pulse generation circuitrywithin the EA device housing, wherein stimulation pulses of thestimulation sessions are applied to body tissue located in the vicinityof the plurality of electrodes; and g) wherein the plurality ofelectrodes are positioned to lie at or near at least one target tissuelocation belonging to the group of target tissue locations consisting ofacupoint GV20, acupoint EXHN3, the nerves underlying acupoints GV20 andEXHN3, and the three branches of the Trigeminal nerve called theinfraorbital, the supraorbital and the supratrochlear.
 16. The IEAS ofclaim 15 wherein the sensor circuitry within the EA housing comprisesmagnetic field sensing circuitry, and wherein the control command isderived from the timing associated with when a magnetic field is presentor absent.
 17. A method for treating at least one of the followingmental disorders of a patient: major depression disorder (MDD),generalized anxiety disorder (Anxiety), bipolar disorder, post-traumaticstress disorder (PTSD), schizophrenia, and obsessive compulsive disorder(OCD), comprising the steps of: (a) implanting an electroacupuncture(EA) device in the patient below the patient's skin at or near at leastone specified target tissue location; (b) enabling the EA device togenerate stimulation sessions at a duty cycle that is less than or equalto 0.05, wherein each stimulation session comprises a series ofstimulation pulses, wherein the duty cycle is the ratio of T3/T4, whereT3 is the duration of each stimulation session, and T4 is the durationbetween stimulation sessions; and (c) delivering the stimulation pulsesof each stimulation session to the at least one specified target tissuelocation through a plurality of electrode arrays electrically connectedto the EA device, where an electrode array comprises an array of nconductive contacts electrically joined together to function jointly asone electrode, where n is an integer.
 18. The method of treating atleast one of the mental disorders MDD, Anxiety, bipolar disorder, PTSD,schizophrenia, and OCD of claim 17 wherein the at least one specifiedtarget tissue location at which the stimulation pulses are applied isselected from the group of target tissue locations consisting ofacupoints EXHN3 and GV20, the nerves underlying acupoints EXHN3 andGV20, and the three branches of the Trigeminal nerve called theinfraorbital, the supraorbital and the supratroclear.
 19. The method oftreating at least one of the mental disorders MDD, Anxiety, bipolardisorder, PTSD, schizophrenia, and OCD of claim 17 further comprisingattaching the plurality of electrode arrays to an outside surface of theEA device, with one electrode array of the plurality of electrode arrayscomprising a central electrode array, and with another electrode arrayof the plurality of electrode arrays comprising an annular electrodearray that surrounds the central electrode array, and wherein thespacing between the center of the central electrode array and theclosest electrode contact within the annular electrode array comprisesat least 5 mm.
 20. The method of treating at least one of the mentaldisorders MDD, Anxiety, bipolar disorder, PTSD, schizophrenia, and OCDof claim 17 further including setting the time T4, the time betweenstimulation sessions, to be at least 1440 minutes [1 day] but no longerthan 20,160 minutes [14 days].
 21. The method of treating at least oneof the mental disorders MDD, Anxiety, bipolar disorder, PTSD,schizophrenia, and OCD of claim 20 further including setting T3, theduration of the stimulation session, to toggle between a first value T3₁for a first stimulation session duration and a second value T3₂ for asecond stimulation session duration, with the value T3₁ being used everyother stimulation session, whereby a time line of the method of treatingmental illness follows a sequence T3₁-T4—T3₂-T4—T3₁-T4—T3₂-T4— . . . andso on, where T4 is the time period between stimulation sessions.
 22. Themethod of treating at least one of the mental disorders MDD, Anxiety,bipolar disorder, PTSD, schizophrenia, and OCD of claim 21 where T3₁ isset to a value that ranges between 10 minutes and 40 minutes, and T3₂ isset to a value that ranges between 30 minutes and 60 minutes.
 23. Themethod of treating at least one of the mental disorders MDD, Anxiety,bipolar disorder, PTSD, schizophrenia, and OCD of claim 20 furtherincluding dividing T3, the duration of the stimulation session, intosmaller segments of time, T31, T32, T33 . . . T3n, where n is aninteger, such that T3=T31+T32+T33+ . . . T3n, and wherein during eachsegment of time the stimulus pulse is delivered at a different frequencythan is delivered during the other segments of time, whereby over thetotal time of the stimulation session T3, the stimulation pulses aredelivered at different frequencies.
 24. The method of treating at leastone of the mental disorders MDD, Anxiety, bipolar disorder, PTSD,schizophrenia, and OCD of claim 17 further including setting the timeT3, the duration of the stimulation sessions, to be at least 10 minutesbut no longer than a maximum value, T3(max), where the value of T3(max)is adjusted, as needed, to maintain the duty cycle, the ratio of T3/T4,at a value no greater than 0.05, wherein T3(max) is equal to 72 minutesif T4, the time period between stimulation sessions, is between 1,440minutes [24 hours] and 20,160 minutes [14 days]; and setting T3(max) toa value set by the equation T3(max)=0.05*T4 when T4 is between 720minutes [1/2 day] and 1,440 minutes [24 hours].
 25. The method oftreating at least one of the mental disorders MDD, Anxiety, bipolardisorder, PTSD, schizophrenia, and OCD of claim 24 further comprisingsetting T4, the time period between stimulation sessions, to togglebetween a first value T4₁ and a second value T4₂, with the value T4₁being used after every other stimulation session, whereby a time line ofthe method of treating mental illness follows a sequenceT3—T4₁-T3-T4₂-T3-T4₁-T3-T4₂-T3—T4₁ . . . and so on, where T3 is theduration of the stimulation sessions.
 26. The method of treating atleast one of the mental disorders MDD, Anxiety, bipolar disorder, PTSD,schizophrenia, and OCD of claim 25 where T4₁ is set to a value thatranges between 720 minutes [½ day] and 10,080 minutes [1 week], and T4₂is set to a value that ranges between 1,440 minutes [1 day] and 20,160minutes [2 weeks].
 27. The method of treating at least one of the mentaldisorders MDD, Anxiety, bipolar disorder, PTSD, schizophrenia, and OCDof claim 17 further including manually starting and stopping thestimulation sessions within parameter boundaries that set a minimumduration, T3(min), for the stimulation session and a maximum duration,T3(max), for the stimulation session; as well as a minimum time period,T4(min), between stimulation sessions and a maximum time period,T4(max), between stimulation sessions, the method comprising: (a)manually starting a stimulation session at any time after aninitialization event; (b) manually stopping the stimulation sessionstarted in step (a) at any time after T3(min) has elapsed, or allowingthe stimulation session started in step (a) to automatically stop afterT3(max) has elapsed; (c) manually starting a new stimulation session atany time after T4(min) has elapsed since the stopping of the stimulationin step (b), or allowing a new stimulation session to automaticallystart after T4(max) has elapsed; (d) repeating steps (b) and (c) for solong as the method for treating mental illness is to be continued, oraborting the treatment by manually shutting down the treatment.
 28. Amethod of treating at least one of the following mental disorders of apatient: major depression disorder (MDD), generalized anxiety disorder(Anxiety), bipolar disorder, post-traumatic stress disorder (PTSD),schizophrenia, and obsessive compulsive disorder (OCD); the method usinga small implantable electroacupuncture device (IEAD) powered by a smalldisc primary battery having a specified nominal output voltage of about3 volts, and having an internal impedance of at least 5 ohms, the IEADbeing configured, using electronic circuitry within the IEAD, togenerate stimulation pulses in accordance with a specified stimulationregimen and apply the stimulation pulses through at least two electrodeslocated outside of the housing of the IEAD at a selected tissuelocation, said at least two electrodes comprising at least one cathodeelectrode and at least one anode electrode, said method comprising: (a)implanting the IEAD below the skin surface of the patient at or near atarget tissue location selected from the group of target tissuelocations consisting of: acupoint EXHN3, acupoint GV20, the nervesunderlying acupoints EXHN3 and GV20, and the three branches of theTrigeminal nerve known as the infraorbital, the supraorbital and thesupratrochlear nerves, and (b) enabling the IEAD to provide EAstimulation pulses in accordance with a stimulation regimen thatprovides a stimulation session having a duration of T3 minutes at a rateof once every T4 minutes, where the ratio of T3/T4 is no greater than0.05, and wherein T3 is at least 10 minutes and no greater than 60minutes.
 29. The method of claim 28 further including setting thestimulation pulses during a stimulation session to have a duration of T1seconds, that occur at a rate of once every T2 seconds, wherein T1 is0.1 to 2.0 milliseconds, and T2 is 100 to 1000 milliseconds.
 30. Themethod of claim 29 wherein the time T2 varies during a stimulationsession, whereby the frequency of the stimulation pulses varies duringthe stimulation session.
 31. The method of claim 28 further includingcontrolling the electronic circuits within the IEAD to limit theinstantaneous current drawn from the small disc primary battery so thatthe output voltage of the primary battery does not drop more than about11% below the output voltage of the primary battery when current isbeing drawn from the primary battery, where the output voltage of theprimary battery is equal to the specified nominal output voltage of theprimary battery less the voltage drop caused by the instantaneouscurrent flowing through the internal impedance of the primary battery.32. The method of claim 31 wherein the electronic circuitry within theIEAD includes a boost converter circuit, and wherein the method ofcontrolling the electronic circuits within the IEAD to limit theinstantaneous current drawn from the battery comprises modulating theoperation of the boost converter circuit between an ON state and an OFFstate.
 33. A method of assembling an implantable electroacupuncturedevice (IEAD) in a small, thin, hermetically-sealed, housing having amaximum linear dimension in a first plane of no more than 25 mm and amaximum linear dimension in a second plane orthogonal to the first planeof no more than 2.5 mm, the housing having at least one feed-through pinassembly radially passing through a wall of the thin housing thatisolates the feed-through pin assembly from high temperatures andresidual weld stresses that occur when the thin housing is welded shutto hermetically-seal its contents, the IEAD being adapted for use intreating mental disorders of a patient, the method comprising the stepsof: (a) forming a thin housing having a bottom case and a top coverplate, the top cover plate being adapted to fit over the bottom case,the bottom case having a maximum linear dimension of no more than 25 mm;(b) forming a recess in a wall of the housing; (c) placing afeed-through assembly within the recess so that a feed-through pin ofthe feed-through assembly electrically passes through a wall of therecess at a location that is separated from where the wall of thehousing is designed to contact the top cover plate; and (d) welding thetop cover plate to the bottom case around a perimeter of the bottomcase, thereby hermetically sealing the bottom case and top casetogether.
 34. An Implantable ElectroAcupuncture System (IEAS) fortreating at least one of the following mental disorders of a patient:major depression disorder (MDD), generalized anxiety disorder (Anxiety),bipolar disorder, post-traumatic stress disorder (PTSD), schizophrenia,and obsessive compulsive disorder (OCD); the IEAS comprising (a) atleast one external component, and (b) a small, thin implantablecomponent having a maximum linear dimension in a first plane of lessthan 25 mm, and a maximum linear dimension in a second plane orthogonalto the first plan of no more than 2.5 mm; wherein the at least oneexternal component comprises an electromagnetic field generator; andwherein the small, thin implantable component comprises: a housing madeof a bottom part and a top part that are welded together to create anhermetically-sealed, closed container, at least one feed-throughterminal that passes through a portion of a wall of the top part orbottom part, and which allows electrical connection to be made betweenthe inside of the closed container and a location on the outside of theclosed container, electronic circuitry inside of the closed containerthat, when enabled, generates stimulation pulses during a stimulationsession, the stimulation session having a duration of T3 minutes, andwherein the electronic circuitry generates a new stimulation session ata rate of once every T4 minutes, where the ratio of T3/T4 is no greaterthan 0.05, wherein the stimulation pulses are coupled to the at leastone feed-through terminal, a sensor on the inside of the closedcontainer adapted to sense the presence or absence of an electromagneticfield, a power source inside of the closed container that providesoperating power for the electronic circuitry, and a plurality ofelectrodes/arrays located on an outside surface of the closed housing,at least one of which is electrically connected to the at least onefeed-through terminal, whereby the stimulation pulses contained in thestimulation sessions are made available to stimulate body tissue incontact with or near the plurality of electrodes on the outside of theclosed housing; and wherein the at least one external componentmodulates an electromagnetic field which, when sensed by the sensorinside of the closed container, conveys information to the electroniccircuitry inside of the closed housing that controls when and how longthe stimulation sessions are applied through the plurality ofelectrodes/arrays.
 35. The IEAS of claim 34 further including at leastone recess in the top or bottom part of the small, thin housing wherethe at least one feed-through terminal passes through a portion of thewall of the top or bottom part, the recess providing thermal andmechanical isolation for the feed-through terminal from the hightemperatures and residual weld stresses created when the top and bottomparts of the housing are welded together.
 36. The IEAS of claim 34wherein the plurality of electrodes/arrays comprise one cathodeelectrode/array and one anode electrode/array located on the outsidesurface of the top or bottom parts of the housing, said cathodeelectrode/array and anode electrode/array being spaced apart by adistance of at least 5 mm.